69048-73-3Relevant academic research and scientific papers
Synthetic study of biphenylquinolizidine alkaloids I. Asymmetric total synthesis of lasubine I featuring organocatalyzed asymmetric intramolecular aza-Michael addition
Hirama, Taku,Umemura, Takayuki,Kogure, Noriyuki,Kitajima, Mariko,Takayama, Hiromitsu
, p. 223 - 226 (2016/12/28)
A new procedure for the asymmetric total synthesis of lythraceous alkaloids with a 4-arylquinolizidine skeleton was developed, which involved an organocatalyzed asymmetric intramolecular aza-Michael addition.
Regioselective cleavage reaction of the aromatic methylenedioxy ring. V. Cleavage with sodium alkoxides-alcohols, potassium tert-butoxide-alcohols, dimsyl anion-methyl alcohol, metallic sodium-alcohols, and sodium cyanide in dipolra aprotic solvents
Imakura,Okimoto,Konishi,Hisazumi,Yamazaki,Kobayashi,Yamashita
, p. 1691 - 1696 (2007/10/02)
The reaction of aromatic methylenedioxy compounds containing electron-withdrawing groups with dimsyl anion-methyl alcohol, potassium tert-butoxide-alcohols, and metallic sodium-alcohols in dimethyl sulfoxide (DMSO), and with sodium alkoxides-alcohols in hexamethylphosphoramide, gave 3- and 4-hydroxybenzene derivatives in good yield by regioselective attack of the alkoxide ions on the methylenedioxy ring. The formation mechanism of alkoxide ions and the effect of DMSO in the cleavage reaction of the methylenedioxy ring are discussed on the basis of proton nuclear magnetic resonance (1H-NMR) spectra. The reactions of aromatic methylenedioxy compounds (3 and 22) with sodium cyanide in dipolar aprotic solvents gave 4-cyano-3-hydroxybenzene derivatives (23 and 24) by regioselective attack of the cyanide ion on the methylenedioxy ring. The reactions of aromatic methylenedioxy compounds (28-30) containing no electron-withdrawing group with MeONa-MeOH in dipolar aprotic solvents gave non-regioselective cleavage products (31 and 34).
Cleavage of the Methylenedioxy Ring. III. Cleavage with Sodium Benzyloxide in Dimethyl Sulfoxide
Kobayashi, Shigeru,Okimoto, Kazuto,Imakura, Yasuhiro
, p. 1567 - 1573 (2007/10/02)
Cleavage of the methylenedioxy ring in aromatic formyl (1-3), nitro (4 and 5), and acetyl (30) compounds with N-sodium benzyloxide-benzyl alcohol in dimethyl sulfoxide gave 3-hydroxybenzene derivatives (19, 22-24, 26, 27, and 33).In the case of the acetyl compound 30, the 4-hydroxybenzene derivative (34) was also obtained as a minor product.Regioselective cleavage of the ring in aromatic compounds having electronwithdrawing groups with nucleophilic oxide anions is discussed.Cleavage of the ring in 1-5 and 30 with 2 N sodium methoxide in dimethyl sulfoxide-dimethylformamide was found to be useful for the practical preparation of 3-hydroxybenzene derivatives (6-10 and 31).Keywords - Cleavage of methylenedioxy ring; regioselectivity; piperonals; 3,4-methylenedioxy-nitrobenzene; 3,4-methylenedioxy-acetophenone; sodium methoxide; sodium phenoxide; sodium benzyloxide; dimethyl sulfoxide; dimethylformamide
Cleavage of Methylenedioxy Ring. II. Cleavage with Sodium Phenoxide and Methoxide in Dimethyl Sulfoxide
Kobayashi, Shigeru,Imakura, Yasuhiro,Horikawa, Ritsuko
, p. 1287 - 1293 (2007/10/02)
Regioselective cleavage of the methylenedioxy ring in piperonals (1, 6, and 7) and 3,4-methylenedioxynitrobenzenes (8 and 9) by oxide ions in dimethyl sulfoxide was achieved: the 4-hydroxybenzene derivatives (2, 10-13, and 22) were obtained with the phenoxide ion, while the 3-hydroxybenzene derivatives (4, 18-21, 23, 26, and 29) were obtained with the methoxide or benzyloxide ion.Keywords - cleavage of methylenedioxy ring; regioselectivity; piperonals; 3,4-methylenedioxynitrobenzenes; sodium phenoxide; sodium methoxide; dimethyl sulfoxide; 3-hydroxybenzene derivatives; 4-hydroxybenzene derivatives; NMR spectra
