Regiospecific acylation of acetals. A convenient method to obtain β-methoxyvinyl trichloromethyl ketones
摘要:
The regiochemistry of the acylation of enol ethers, generated in situ, from acetals of unsymmetrical ketones is reported. These results demonstrate a convenient one-pot method to obtain a series of beta-methoxyvinyl trichloromethyl ketones [CCl3COCH=C(OMe)R, where R=Et, n-Bu, i-Pr, (CH2)(2)C(OMe)=CHC(O)CCl3 and (CH2)(5)CO2CH3)] in high yields. (C) 1999 Elsevier Science Ltd. All rights reserved.
A Convenient Preparation of 4-Methyl- and 4-Phenylseleno-1,1,1-trihalo-3-alken-2-ones and their Usefulness in the Synthesis of 3-Trihalomethylisoselenazoles
作者:Marcos A. Martins、Giovani P. Bastos、Adilson P. Sinhorin、Nilo E. Zimmermann、Helio G. Bonacorso、Nilo Zanatta
DOI:10.1055/s-2002-34854
日期:——
reaction of 4-methylseleno- 1,1,1-trihalo-3-alken-2-ones with bromine and ammonia lead to 3-trihalomethylisoselenazoles in good yields. The usefulness of the trichloromethylgroup as a carboxyl group precursor was demonstrated by the conversion of 5-ethyl-3-trichloromethylisoselenazole to 5-ethyl-3-carboxyisoselenazole acid.
A simple and convenient one-pot procedure for the synthesis of 5- and 6-substituted 2-phenyl-3 H-pyrimidin-4-ones by the condensation of 4-alkoxy-1,1,1-trichloroalk-3-en-2-ones with benz-amidine hydrochloride is described.
A Convenient Synthesis of 5-Trichloromethyl-5-hydroxy-3-heteroalkyl-4,5-dihydroisoxazoles
作者:Marcos A. P. Martins、Adilson P. Sinhorin、Nilo E. K. Zimmermann、Nilo Zanatta、Helio G. Bonacorso、Giovani P. Bastos
DOI:10.1055/s-2001-17701
日期:——
A synthetic strategy to obtain a series of 3-heteroalkyl-4,5-dihydroisoxazoles, which is based on the cyclocondensation reaction of 5-heteroalkyl-1,1,1-trichloro-4-methoxy-3-penten[hexen]-2-ones 1a-g, 2a-g with hydroxylamine has been developed. The preparation of 1,1,1-trichloro-5-heteroalkyl-4-methoxy-3-penten[hexen]-2-ones in good yields is also described.
ABSTRACT The one-pot synthesis of nine 5-trichloromethyl-1,2-dimethyl-1H-pyrazolium chlorides 2 from the cyclocondensation of 4-alkoxy-1,1,1-trichloro-3-alken-2-ones [CCl3C(O)C(R2)= C(R1)OR, where R1 = H, Me, Et, n-Pr, (CH2)5CO2Et, CH2Br, Ph, 4-Br-C6H4; R2 = H, Me; and R = Me, Et] with 1,2-dimethylhydrazine is reported. For Part 16, see Ref. [12].
HALOACETYLATED ENOL ETHERS: 16[5] REGIOSPECIFIC SYNTHESIS OF 5-TRICHLOROMETHYL-PYRAZOLES
作者:Alex F. C. Flores、Marcos A. P. Martins、Adriano Rosa、Darlene Correia Flores、Nilo Zanatta、Helio G. Bonacorsso
DOI:10.1081/scc-120004150
日期:2002.1
ABSTRACT The regiospecific synthesis and isolation of three series of 5-trichloromethyl-pyrazoles 2f–j, 3a–j and 4a–j from the cyclocondensation of 1,1,1-trichloro-4-alkoxy-3-alken-2-ones (1a–f) or trichloroacetyl containing β-diketones (1g–j) with dry hydrazine and phenyl-hydrazine is reported. It was established by 1H- and 13C-NMR spectroscopy that the 5-hydroxy-5-trichloromethyl-4,5-dihydro-1H-pyrazole