Biological Assays The tyrosinase inhibition activity of the compounds was measured using l-DOPA like a substrate according to a modified method of previous work [4,10,11]. wide range of pharmacological activities of WEL were reported, there is less info within the inhibitory effect and reversibility of WEL on tyrosinase. Thus, the inhibitory activity and mechanism of WEL toward tyrosinase deserves deeper investigation; however, but the present knowledge on synthesis of the natural product is limited. Although several organizations invested substantial effort in the preparation of WEL, these methods had several disadvantages, including a time-consuming nature with complicated synthetic methods [13,14,15]. Among these methods, two routes outlined in Number 1 are commonly identified by the market. However, both methods have several disadvantages. The first method (reported by Yang [14]) entails a crucial intermediate, phenyl acetylene, which is definitely difficult to prepare. The route has a low 15% overall yield with a long linear sequence (total of 12 methods), and it is rarely applied to access a variety of WEL analogues for structure transformations. The second method (reported by Lee et al. [13]) employs harmful organotin and organomercurial reagents, which limit industrial production and increase operation difficulty. In addition, both methods can only have the natural products on a small scale. As the present methods are imperfect and unsatisfactory for further investigation of WEL as an efficient tyrosinase inhibitor, the development of a facile, versatile, and slight approach is definitely urgently needed. Open in a Dimethocaine separate window Number 1 Reported synthesis routes of wedelolactone (WEL) and our proposal. 2. Results and Discussion 2.1. Palladium(II)-Catalyzed Efficient Synthesis of WEL Retrosynthetically, WEL could be logically disconnected from the ring opening of furan to afford the intermediate 4, which is definitely further disconnected by CCC relationship cleavage to trace back to the intermediate 3-bromo-5-benzyloxy-7-acetoxyl-2-chromenone 3 and the readily prepared 4,5-dibenzyloxy-2-(4-methoxybenzyl)oxy-phenyl boronic ester 2 (Plan 1). This related synthetic strategy was ever used by Shen for the synthesis of hirtellanine A [16]. Synthetically, we expected that polysubstituted coumarin 4 could be obtained by Pd(II)-catalyzed SuzukiCMiyaura coupling of 3-bromocoumarin 3 and polysubstituted phenyl boronate ester 2 which could be generated by a Pd(II)-catalyzed boronation reaction of the polysubstituted bromobenzene 1. The coupling product 4 then underwent a DDQ-oxidation deprotection/annulation reaction to deliver the final product WEL 5. In the beginning of our synthesis, we focused on the generation of the polysubstituted bromobenzene 1 (Scheme 1). Selective protection of the three phenolic hydroxyl groups presented a big synthetic challenge. After reviewing the literature [16,17], we chose the commercially available 3,4-dihydroxybenzaldehyde 6 as the starting material to provide the polysubstituted bromobenzene 1 via the = 8.1 Hz, 1H), 7.34C7.52 (m, = 12.0 Hz, 12 Hz), 9.84 (s, 1H); 13C-NMR (CDCl3, 75 MHz): 70.4, Dimethocaine 70.5, 112.0, 112.7, 126.2, 126.6, 126.8, 127.5, 127.6, 128.1, 128.2, 129.9, 135.8, 136.1, 148.8, 153.9, 190.3 ppm; HR-MS (ESI) calculated for C21H19O3 [M + H] 319.1334, found 319.1330. Preparation of = 8.7 Hz, 1H), 6.88 (d, = 8.7 Hz, 1H), 6.93 (s, 1H), 6.95 (s, 1H), 7.33C7.46 (m, 12H); 13C-NMR (CDCl3, 75 MHz): 54.8, 69.8, 70.6, 72.2, 103.4, 105.2, 113.5, 116.6, 126.9, 127.1, 127.2, 127.3, 127.9, 128.0, 128.6, 128.8, 136.6, 137.2, 142.7, 149.7, 153.7, 159.0 ppm; HR-MS (ESI) calculated for C28H27O4 [M + H] 427.1909, found 427.1909. Preparation of = 8.7 Hz, 2H), 7.17 (s, 1H), 7.33C7.46 (m, 12H); 13C-NMR (CDCl3, 75 MHz): 54.8, 71.4, 71.5, 72.1, 103.0, 104.4, 113.5, 120.1, 126.9, 127.1, 127.4, 127.5, 128.0, 128.1, 128.2, 128.5, 136.3, 136.5, 143.7, 148.5, 149.5, 158.9 ppm; HR-MS (ESI) calculated for C28H25BrKO4 [M + K] 543.0573, found 543.0559. Preparation of = 9.6 Hz, 1H), 6.09 (m, 1H), 6.17 (d, = 2.1 Hz, 1H),.Conclusions In summary, we developed an efficient synthetic route to synthesize wedelolactone, wherein Pd(II)-catalyzed boronation/coupling reactions and DDQ-involved oxidative deprotection/annulation are key reactions. the inhibitory activity and mechanism of WEL toward tyrosinase deserves deeper investigation; however, but the present knowledge on synthesis of the natural product is limited. Although several groups invested substantial effort in the preparation of WEL, these methods had several disadvantages, including a time-consuming nature with complicated synthetic approaches [13,14,15]. Among these methods, two routes listed in Physique 1 are commonly recognized by the industry. However, both methods Dimethocaine have several disadvantages. The first method (reported by Yang [14]) involves a crucial intermediate, phenyl acetylene, which is usually difficult to prepare. The route has a low 15% overall yield with a long linear sequence (total of 12 actions), and it is rarely applied to access a variety of WEL analogues for structure transformations. The second method (reported by Lee et al. [13]) employs toxic organotin and organomercurial reagents, which limit industrial production and increase operation complexity. In addition, both methods can only obtain the natural products on a small scale. As the present methods are imperfect and unsatisfactory for further investigation of WEL as an efficient tyrosinase inhibitor, the development of a facile, versatile, and mild approach is urgently needed. Open in a separate window Physique 1 Reported synthesis routes of wedelolactone (WEL) and our proposal. 2. Results and Discussion 2.1. Palladium(II)-Catalyzed Efficient Synthesis of WEL Retrosynthetically, WEL could be logically disconnected by the ring opening of furan to afford the intermediate 4, which is usually further disconnected by CCC bond cleavage to trace back to the intermediate 3-bromo-5-benzyloxy-7-acetoxyl-2-chromenone 3 and the readily prepared 4,5-dibenzyloxy-2-(4-methoxybenzyl)oxy-phenyl boronic ester 2 (Scheme 1). This comparable synthetic strategy was ever used by Shen for the synthesis of hirtellanine A [16]. Synthetically, we expected that polysubstituted coumarin 4 could be obtained by Pd(II)-catalyzed SuzukiCMiyaura coupling of 3-bromocoumarin 3 and polysubstituted phenyl boronate ester 2 which could be generated by a Pd(II)-catalyzed boronation reaction of the polysubstituted bromobenzene 1. The coupling product 4 then underwent a DDQ-oxidation deprotection/annulation reaction to deliver the final product WEL 5. In the beginning of our synthesis, we focused on the generation of the polysubstituted bromobenzene 1 (Scheme 1). Selective protection of the three phenolic hydroxyl groups presented a big synthetic challenge. After reviewing the literature [16,17], we chose the commercially available 3,4-dihydroxybenzaldehyde 6 as the starting material to provide the polysubstituted bromobenzene 1 via the = 8.1 Hz, 1H), 7.34C7.52 (m, = 12.0 Hz, 12 Hz), 9.84 (s, 1H); 13C-NMR (CDCl3, 75 MHz): 70.4, 70.5, 112.0, 112.7, 126.2, 126.6, 126.8, 127.5, 127.6, 128.1, 128.2, 129.9, 135.8, 136.1, 148.8, 153.9, 190.3 ppm; HR-MS (ESI) calculated for C21H19O3 [M + H] 319.1334, found 319.1330. Preparation of = 8.7 Hz, 1H), 6.88 (d, = 8.7 Hz, 1H), 6.93 (s, 1H), 6.95 (s, 1H), 7.33C7.46 (m, 12H); 13C-NMR (CDCl3, 75 MHz): 54.8, 69.8, 70.6, 72.2, 103.4, 105.2, 113.5, 116.6, 126.9, 127.1, 127.2, 127.3, 127.9, 128.0, 128.6, 128.8, 136.6, 137.2, 142.7, 149.7, 153.7, 159.0 ppm; HR-MS (ESI) calculated for C28H27O4 [M + H] 427.1909, found 427.1909. Preparation of = 8.7 Hz, 2H), 7.17 (s, 1H), 7.33C7.46 (m, 12H); 13C-NMR (CDCl3, 75 MHz): 54.8, 71.4, 71.5, 72.1, 103.0, 104.4, 113.5, 120.1, 126.9, 127.1, 127.4, 127.5, 128.0, 128.1, 128.2, 128.5, 136.3, 136.5, 143.7, 148.5, 149.5, 158.9 ppm; HR-MS.After the reaction was finished, the mixture was concentrated and then purified by column chromatography (MeOH:DCM = 1:20) to give the product 5. of WEL on tyrosinase. Thus, the inhibitory activity and mechanism of WEL toward tyrosinase deserves deeper investigation; however, but the present knowledge on synthesis of the organic item is bound. Although several organizations invested substantial work in the planning of WEL, these procedures had several drawbacks, including a time-consuming character with complicated artificial techniques [13,14,15]. Among these procedures, two routes detailed in Shape 1 are generally identified by the market. However, both strategies have several drawbacks. The first technique (reported by Yang [14]) requires an essential intermediate, phenyl acetylene, which can be difficult to get ready. The route includes a low 15% general yield with an extended linear series (total of 12 measures), which is rarely put on access a number of WEL analogues for framework transformations. The next technique (reported by Lee et al. [13]) uses poisonous organotin and organomercurial reagents, which limit commercial production and boost operation complexity. Furthermore, both methods can only just have the natural basic products on a little scale. As today’s strategies are imperfect and unsatisfactory for even more analysis of WEL as a competent tyrosinase inhibitor, the introduction of a facile, flexible, and mild strategy is urgently required. Open in another window Shape 1 Reported synthesis routes of wedelolactone (WEL) and our proposal. 2. Outcomes and Dialogue 2.1. Palladium(II)-Catalyzed Efficient Synthesis of WEL Retrosynthetically, WEL could possibly be logically disconnected from the band starting of furan to cover the intermediate 4, which can be additional disconnected by CCC relationship cleavage to track back again to the intermediate 3-bromo-5-benzyloxy-7-acetoxyl-2-chromenone 3 as well as the easily ready 4,5-dibenzyloxy-2-(4-methoxybenzyl)oxy-phenyl boronic ester 2 (Structure 1). This identical synthetic technique was ever utilized by Shen for the formation of hirtellanine A [16]. Synthetically, we anticipated that polysubstituted coumarin 4 could possibly be acquired by Pd(II)-catalyzed SuzukiCMiyaura coupling of 3-bromocoumarin 3 and polysubstituted phenyl boronate ester 2 that could become generated with a Pd(II)-catalyzed boronation result of the polysubstituted bromobenzene 1. The coupling item 4 after that underwent a DDQ-oxidation deprotection/annulation a reaction to deliver the ultimate item WEL 5. Initially of our synthesis, we centered on the era from the polysubstituted bromobenzene 1 (Structure 1). Selective safety from the three phenolic hydroxyl organizations presented a large synthetic problem. After looking at the books [16,17], we find the commercially obtainable 3,4-dihydroxybenzaldehyde 6 as the beginning material to supply the polysubstituted bromobenzene 1 via the = 8.1 Hz, 1H), 7.34C7.52 (m, = 12.0 Hz, 12 Hz), 9.84 (s, 1H); 13C-NMR (CDCl3, 75 MHz): 70.4, 70.5, 112.0, 112.7, 126.2, 126.6, 126.8, 127.5, 127.6, 128.1, 128.2, 129.9, 135.8, 136.1, 148.8, 153.9, 190.3 ppm; HR-MS (ESI) determined for C21H19O3 [M + H] 319.1334, found 319.1330. Planning of = 8.7 Hz, 1H), 6.88 (d, = 8.7 Hz, 1H), 6.93 (s, 1H), 6.95 (s, 1H), 7.33C7.46 (m, 12H); 13C-NMR (CDCl3, 75 MHz): 54.8, 69.8, 70.6, 72.2, 103.4, 105.2, 113.5, 116.6, 126.9, 127.1, 127.2, 127.3, 127.9, 128.0, 128.6, 128.8, 136.6, 137.2, 142.7, 149.7, 153.7, 159.0 ppm; HR-MS (ESI) determined for C28H27O4 [M + H] 427.1909, found 427.1909. Planning of = 8.7 Hz, 2H), 7.17 (s, 1H), 7.33C7.46 (m, 12H); 13C-NMR (CDCl3, 75 MHz): 54.8, 71.4, 71.5, 72.1, 103.0, 104.4, 113.5, 120.1, 126.9, 127.1, 127.4, 127.5, 128.0, 128.1, 128.2, 128.5, 136.3, 136.5, 143.7, 148.5, 149.5, 158.9 ppm; HR-MS (ESI) determined for C28H25BrKO4 [M + K] 543.0573, found 543.0559. Planning of = 9.6 Hz, 1H), 6.09 (m, 1H), 6.17 (d, = 2.1 Hz, 1H), 7.86 (dd, = 5.7, 9.6 Hz, 1H), 10.28 (s, 1H), 10.56 (s, 1H); 13C-NMR (DMSO= 9.6 Hz, 1H), 7.11 (d, = 2.1 Hz, 1H), 7.24 (dd, = 0.6, 2.1 Hz, 1H), 8.07 (dd, = 0.6, 9.6 Hz, 1H); 13C-NMR (DMSO= 1.3 Hz, 1H), 6.98 (d, = 1.6 Hz, 1H), 7.36C7.45 (m, 3H), 7.51C7.54 (m, 2H), 8.39 (s, 1H); 13C-NMR (DMSO= 0.9 Hz, 2H), 6.76 (s, 1H), 6.79 (s, 1H), 7.00 (s, 1H), 7.11 (s, 1H), 7.20 (s, 1H), 7.23 (s, 1H), 7.30C7.44 (m, 11H), 7.46C7.49 (m, 4H), 7.90 (s, 1H); 13C-NMR (DMSO= 2.1 Hz, 1H), 6.63 (d, = 2.1 Hz, 1H), 7.20 (s, 1H), 7.37C7.63 (m, 15H), 7.68 (s, Dimethocaine 1H); 13C-NMR (CDCl3, 75 MHz): 55.8, 70.8, 71.8, 72.0, 94.1, 97.1, 99.4, 105.5, 116.2, 126.8, 127.3, 127.5, 127.9, 128.0, 128.1, 128.5, 128.6, 128.7, 136.2, 136.8, 137.0, 148.0, 148.5, 150.1, 155.4, 155.9, 158.5, 159.7, 162.8; HR-MS (ESI) determined for C37H28NaO7 [M + Na] 607.1733, found.Synthetically, we expected that polysubstituted coumarin 4 could possibly be obtained simply by Pd(II)-catalyzed SuzukiCMiyaura coupling of 3-bromocoumarin 3 and polysubstituted phenyl boronate ester 2 that could be generated with a Pd(II)-catalyzed boronation result of the polysubstituted bromobenzene 1. system of WEL toward tyrosinase should get deeper investigation; nevertheless, however the present understanding on synthesis from the organic item is bound. Although several organizations invested substantial work in the planning of WEL, these procedures had several drawbacks, including a time-consuming character with complicated artificial techniques [13,14,15]. Among these procedures, two routes detailed in Shape 1 are generally identified by the market. However, both strategies have several drawbacks. The first technique (reported by Yang [14]) requires an essential intermediate, phenyl acetylene, which can be difficult to get ready. The route includes a low 15% general yield with an extended linear series (total of 12 measures), which is rarely put on access a number of WEL analogues for framework transformations. The next technique (reported by Lee et al. [13]) uses poisonous organotin and organomercurial reagents, which limit commercial production and boost operation complexity. Furthermore, both methods can only just have the natural basic products on a little scale. As today’s strategies are imperfect and unsatisfactory for even more analysis of WEL as a competent tyrosinase inhibitor, the introduction of a facile, flexible, and mild strategy is urgently required. Open in another window Shape 1 Reported synthesis routes of wedelolactone (WEL) and our proposal. 2. Outcomes and Debate 2.1. Palladium(II)-Catalyzed Efficient Synthesis of WEL Retrosynthetically, WEL could possibly be logically disconnected with the band starting of furan to cover the intermediate 4, which is normally additional disconnected by CCC connection cleavage to track back again to the intermediate 3-bromo-5-benzyloxy-7-acetoxyl-2-chromenone 3 as well as the easily ready 4,5-dibenzyloxy-2-(4-methoxybenzyl)oxy-phenyl boronic ester 2 (System 1). This very similar synthetic technique was ever utilized by Shen for the formation of hirtellanine A [16]. Synthetically, we anticipated that polysubstituted coumarin 4 could possibly be attained by Pd(II)-catalyzed SuzukiCMiyaura coupling of 3-bromocoumarin 3 and polysubstituted phenyl boronate ester 2 that could end up being generated with a Pd(II)-catalyzed boronation result of the polysubstituted bromobenzene 1. The coupling item 4 after that underwent a DDQ-oxidation deprotection/annulation a reaction to deliver the ultimate item WEL 5. Initially of our synthesis, we centered on the era from the polysubstituted bromobenzene 1 (System 1). Selective security from the three phenolic hydroxyl groupings presented a huge synthetic problem. After researching the books [16,17], we find the commercially obtainable 3,4-dihydroxybenzaldehyde 6 as the beginning material to supply the polysubstituted bromobenzene 1 via the = 8.1 Hz, 1H), 7.34C7.52 (m, = 12.0 Hz, 12 Hz), 9.84 (s, 1H); 13C-NMR (CDCl3, 75 MHz): 70.4, 70.5, 112.0, 112.7, 126.2, 126.6, 126.8, 127.5, 127.6, 128.1, 128.2, 129.9, 135.8, 136.1, 148.8, 153.9, 190.3 ppm; HR-MS (ESI) computed for C21H19O3 [M + H] 319.1334, found 319.1330. Planning of = 8.7 Hz, 1H), 6.88 (d, = 8.7 Hz, 1H), 6.93 (s, 1H), 6.95 (s, 1H), 7.33C7.46 (m, 12H); 13C-NMR (CDCl3, 75 MHz): 54.8, 69.8, 70.6, 72.2, 103.4, 105.2, 113.5, 116.6, 126.9, 127.1, 127.2, 127.3, 127.9, 128.0, 128.6, 128.8, 136.6, 137.2, 142.7, 149.7, 153.7, 159.0 ppm; HR-MS (ESI) computed for C28H27O4 [M + H] 427.1909, found 427.1909. Planning of = 8.7 Hz, 2H), 7.17 (s, 1H), 7.33C7.46 (m, 12H); 13C-NMR (CDCl3, 75 MHz): 54.8, 71.4, 71.5, 72.1, 103.0, 104.4, 113.5, 120.1, 126.9, 127.1, 127.4, 127.5, 128.0, 128.1, 128.2, 128.5, 136.3, 136.5, 143.7, 148.5, 149.5, 158.9 ppm; HR-MS (ESI) computed for C28H25BrKO4 [M + K] 543.0573, found 543.0559. Planning of = 9.6 Hz, 1H), 6.09 (m, 1H), 6.17 (d, = 2.1 Hz, 1H), 7.86 (dd, = 5.7, 9.6 Hz, 1H), 10.28 (s, 1H), 10.56 (s, 1H); 13C-NMR (DMSO= 9.6 Hz, 1H), 7.11 (d, = 2.1 Hz, 1H), 7.24 (dd, = 0.6, 2.1 Hz, 1H), 8.07 (dd, = 0.6, 9.6 Hz, 1H); 13C-NMR (DMSO= 1.3 Hz, 1H), 6.98 (d, = 1.6 Hz, 1H), 7.36C7.45 (m, 3H), 7.51C7.54 (m, 2H), 8.39 (s, 1H); 13C-NMR (DMSO= 0.9 Hz, 2H), 6.76 (s, 1H), 6.79 (s, 1H), 7.00 (s, 1H), 7.11 (s, 1H), 7.20 (s, 1H), 7.23 (s, 1H), 7.30C7.44 (m, 11H), 7.46C7.49 (m, 4H), 7.90 (s, 1H); 13C-NMR (DMSO= 2.1 Hz, 1H), 6.63 (d, = 2.1 Hz, 1H), 7.20 (s, 1H), 7.37C7.63 (m, 15H), 7.68 (s, 1H); 13C-NMR (CDCl3, 75 MHz): 55.8, 70.8,.The percentage inhibition of tyrosinase activity was calculated the following: % inhibition = [1 ? (X ? A1)/(A2 ? A1)] 100%, where X may be the absorbance at 475 nm from the inhibitor, A1 may be the absorbance at 475 nm of the answer without tyrosinase, and A2 may be the absorbance at 475 nm of the lender (without inhibitor). 4. areas. [12]. Although an array of pharmacological actions of WEL had been reported, there is certainly less information over the inhibitory impact and reversibility of WEL on tyrosinase. Hence, the inhibitory activity and system of WEL toward tyrosinase deserves deeper analysis; however, however the present understanding on synthesis from the organic item is bound. Although several groupings invested substantial work in the planning of WEL, these procedures had several drawbacks, including a time-consuming character with complicated artificial strategies [13,14,15]. Among these procedures, two routes shown in Amount 1 are generally acknowledged by the sector. However, both strategies have several drawbacks. The first technique (reported by Yang [14]) consists of an essential intermediate, phenyl acetylene, which is normally difficult to get ready. The route includes a low 15% general yield with an extended linear series (total of 12 techniques), which is rarely put on access a number of WEL analogues for framework transformations. The next technique (reported by Lee et al. [13]) uses dangerous organotin and organomercurial reagents, which limit commercial production and boost operation complexity. Furthermore, both methods can only just get the natural basic products on a little scale. As today’s strategies are imperfect and unsatisfactory for even more analysis of WEL as a competent tyrosinase inhibitor, the introduction of a facile, flexible, and mild strategy is urgently required. Open in another window Amount 1 Reported synthesis routes of wedelolactone (WEL) and our proposal. 2. Outcomes and Debate 2.1. Palladium(II)-Catalyzed Efficient Synthesis of WEL Retrosynthetically, WEL could possibly be logically disconnected with the band starting of furan to cover the intermediate 4, which is normally additional disconnected by CCC connection cleavage to track back again to the intermediate 3-bromo-5-benzyloxy-7-acetoxyl-2-chromenone 3 as well as the easily ready 4,5-dibenzyloxy-2-(4-methoxybenzyl)oxy-phenyl boronic ester 2 (System 1). This very similar synthetic technique was ever utilized by Shen for the formation of hirtellanine A [16]. Synthetically, we anticipated that polysubstituted coumarin 4 could possibly be attained by Pd(II)-catalyzed SuzukiCMiyaura coupling of 3-bromocoumarin 3 and polysubstituted phenyl boronate ester 2 that could end up being generated with a Pd(II)-catalyzed boronation result of the polysubstituted bromobenzene 1. The coupling item 4 after that underwent a DDQ-oxidation deprotection/annulation a reaction to deliver the ultimate item WEL 5. Initially of our synthesis, we centered on the era from the polysubstituted bromobenzene 1 (System 1). Dimethocaine Selective security from the three phenolic hydroxyl groupings presented a huge synthetic problem. After researching the books [16,17], we find the commercially obtainable 3,4-dihydroxybenzaldehyde 6 as the beginning material to supply the polysubstituted bromobenzene 1 via the = 8.1 Hz, 1H), 7.34C7.52 (m, = 12.0 Hz, 12 Hz), 9.84 (s, 1H); 13C-NMR (CDCl3, 75 MHz): 70.4, 70.5, 112.0, 112.7, 126.2, 126.6, 126.8, 127.5, 127.6, 128.1, 128.2, 129.9, 135.8, 136.1, 148.8, 153.9, 190.3 ppm; HR-MS (ESI) computed for C21H19O3 [M + H] 319.1334, found 319.1330. Planning of = 8.7 Hz, 1H), 6.88 (d, = 8.7 Hz, 1H), 6.93 (s, 1H), 6.95 (s, 1H), 7.33C7.46 (m, 12H); 13C-NMR (CDCl3, 75 MHz): 54.8, 69.8, 70.6, 72.2, 103.4, 105.2, 113.5, 116.6, 126.9, 127.1, 127.2, 127.3, 127.9, 128.0, 128.6, 128.8, 136.6, 137.2, 142.7, 149.7, 153.7, 159.0 ppm; HR-MS (ESI) computed for C28H27O4 [M + H] 427.1909, found 427.1909. Planning of = 8.7 Hz, 2H), 7.17 (s, 1H), 7.33C7.46 (m, 12H); 13C-NMR (CDCl3, 75 MHz): 54.8, 71.4, 71.5, 72.1, 103.0, 104.4, 113.5, 120.1, 126.9, 127.1, 127.4, 127.5, 128.0, Mctp1 128.1, 128.2, 128.5, 136.3, 136.5, 143.7, 148.5, 149.5, 158.9 ppm; HR-MS (ESI) computed for C28H25BrKO4 [M + K] 543.0573, found 543.0559. Planning of = 9.6 Hz, 1H), 6.09 (m, 1H), 6.17 (d, = 2.1 Hz, 1H), 7.86 (dd, = 5.7, 9.6 Hz, 1H), 10.28 (s, 1H), 10.56 (s, 1H); 13C-NMR (DMSO= 9.6 Hz, 1H), 7.11 (d, = 2.1 Hz, 1H), 7.24 (dd, = 0.6, 2.1 Hz, 1H), 8.07 (dd, = 0.6, 9.6 Hz, 1H); 13C-NMR (DMSO= 1.3 Hz, 1H), 6.98 (d, = 1.6 Hz, 1H), 7.36C7.45 (m, 3H), 7.51C7.54 (m, 2H), 8.39 (s, 1H); 13C-NMR (DMSO= 0.9 Hz, 2H), 6.76 (s, 1H), 6.79 (s, 1H), 7.00 (s, 1H), 7.11 (s, 1H), 7.20 (s, 1H), 7.23 (s, 1H), 7.30C7.44 (m, 11H), 7.46C7.49 (m, 4H), 7.90 (s, 1H); 13C-NMR (DMSO= 2.1 Hz, 1H), 6.63 (d, = 2.1 Hz, 1H), 7.20 (s, 1H), 7.37C7.63 (m, 15H), 7.68 (s, 1H); 13C-NMR (CDCl3, 75 MHz): 55.8, 70.8, 71.8, 72.0, 94.1, 97.1, 99.4, 105.5,.