Synthesis and absolute configuration of lactone II isolated from Streptomyces sp. Go 40/10

Abstract

All four possible stereoisomers of lactone II isolated from Streptomyces sp. Go 40/10, an autoregulator, have been efficiently synthesized in a stereoselective manner starting from (S)-malic acid and sorbic acid, and the absolute configuration was determined to be 2S, 3S, 9R, 10S.

Angiogenesis Inhibitors and Anti-Inflammatory Agents from Phoma sp. NTOU4195

“…The physical and NMR data of 2 were in accordance with those of 1 , except that the 4′,5′-diol in 1 was substituted by a 4′,5′-epoxide group in 2 , as judged from the characteristic resonances at δ H 3.27 (1H, dd, J = 7.1, 1.8 Hz, H-4′)/δ C 58.7 (C-4′) and δ H 2.98 (1H, dq, J = 5.2, 1.8 Hz, H-5′)/δ C 58.3 (C-5′) in its 1 H (MeOH- d 4 , 500 MHz) and 13 C NMR (MeOH- d 4 , 125 MHz) spectra (Table ). In addition, the relative configurations of H-4′ and H-5′ were deduced to both be the E form, as evidenced by the 3 J H‑4′/H‑5′ of 1.8 Hz, in contrast with that of the cis form ( J = 4.4 Hz) . The HRESIMS of 2 revealed a pseudomolecular ion at m / z 429.2245, 18 Da less than that of 1 , and also confirmed that 2 was a dehydrated analogue of 1 .…”

“…In addition, the relative configurations of H-4′ and H-5′ were deduced to both be the E form, as evidenced by the 3 J H-4′/H-5′ of 1.8 Hz, in contrast with that of the cis form (J = 4.4 Hz). 27 The HRESIMS of 2 revealed a pseudomolecular ion at m/z 429.2245, 18 Da less than that of 1, and also confirmed that 2 was a dehydrated analogue of 1. Hence, 2 was assigned as the structure shown in Figure 1 and named phomaketide B.…”

Stereoselective synthesis and structure of butalactin and lactone II isolated from Streptomyces species

“…A colorless oil, [] D 24 +117.5 (c, 0.56, CHCl 3 );  H (300 MHz, CDCl 3 ) 1.50-1.68 (6H, m), 2.76-2.86 (1H, m), 3.45 (1H, dd, J 7.9 and 9.5), 3.49 (1H, dd, J 5.8 and 9.5), 3.48-3.53 (1H, m), 4.07 (1H, dd, J 7.4 and 10.8), 4.24 (1H, dd, J 5.9 and 9.5), 4.36 (1H, dd, J 2.5 and 9.5), 4…”

“…The extract was dried, and concentrated under reduced pressure to give a diacid (91 mg, 92%) as a colorless oil; [] D 31 −5.2 (c, 0.96, CHCl 3 );  C (75 MHz, CD 3 OD) 50. 4 To a solution of the diacid (40 mg, 0.16 mmol) in 2,2-dimethoxypropane (2 cm 3 ) was added a catalytic amount of p-TsOH, and the mixture was stirred at room temperature for 17 h. The reaction mixture was quenched with saturated aqueous NaHCO 3 , and acidified (pH 4) with aqueous citric acid and extracted with ether. The extract was washed with water and brine, dried, and concentrated under reduced pressure to give the acetonide 10 (41.…”

“…Recently, we achieved the first synthesis of 2a and reported it as a preliminary communication. 4 Herein the synthesis and the stereochemistry of butalactin 1a and lactone II 2a will be described in detail. Our synthetic plan is briefly illustrated in Scheme 1. compound 7, [] D 26 +34.6 (c, 0.9, CHCl 3 ) {ref.…”