Novel rifamycins characterized by the following structural formula ##STR1## WHEREIN Me represents a methyl group, n represents 3, 4, 5 or 6; g represents 0, 1 or 2; and each R represents a lower alkyl group selected from methyl or ethyl substituting for a hydrogen atom of a --CH.sub.2 -- group; and wherein, when g is 2, the two lower alkyl groups may replace hydrogen atoms of two different methylene groups as well as hydrogen atoms of the same methylene group. The compounds of this invention possess a broad spectrum antibacterial utility accompanied by a low toxicity.
Selective reduction of N-nitroso aza-aliphatic cyclic compounds to the corresponding N-amino products using zinc dust in CO2–H2O medium
作者:Weiqing Yang、Xiang Lu、Tingting Zhou、Yongjing Cao、Yuanyuan Zhang、Menglin Ma
DOI:10.1007/s10593-018-2349-0
日期:2018.8
A new method for reduction of N-nitroso aza-aliphatic cyclic compounds employing zinc in pressurized CO2–H2O medium has been developed. H2O and NH4Cl were used as hydrogen donors, and reduction was performed under environmentally benign conditions. The presented approach allowed to obtain the respective N-amino products selectively and in excellent yields (up to 97%).