4-Aminopyridine Catalyzed Direct and Regioselective Acylation of N-Tosylhydrazide
摘要:
An efficient and simple method for selective acylation of either one of two nitrogen atoms of tosylhydrazide was developed. The selectivity was drastically controlled by a catalytic amount of 4-aminopyridine or 4-(dimethylamino)pyridine with common acylating agents. The nitrogen atom masked with a tosyl group was acylated in the presence of 4-aminopyridine, whereas the primary nitrogen atom was acylated in the absence of 4-aminopyridine.
A new and efficient metal-free, two-component, one-pot approach to a variety of 3,5-disubstituted 1H-pyrazoles has been developed from propargylic alcohols. This transformation proceeds via an acid-catalyzed propargylation of N,N-diprotected hydrazines followed by base-mediated 5-endo-dig cyclization leading to 3,5-disubstituted 1H-pyrazoles in good overall yields.
4-Aminopyridine Catalyzed Direct and Regioselective Acylation of <i>N</i>-Tosylhydrazide
An efficient and simple method for selective acylation of either one of two nitrogen atoms of tosylhydrazide was developed. The selectivity was drastically controlled by a catalytic amount of 4-aminopyridine or 4-(dimethylamino)pyridine with common acylating agents. The nitrogen atom masked with a tosyl group was acylated in the presence of 4-aminopyridine, whereas the primary nitrogen atom was acylated in the absence of 4-aminopyridine.
Carbon-Nitrogen Bond Formation between Allyl Silyl Ether and Hydrazide Promoted by Mercuric Triflate Catalyst
An efficient method for carbon–nitrogen bond formation between ally silyl ethers and N , N -acyltosylhydrazine was developed under very mild conditions using 2 mol% of mercuric triflate [Hg(OTf) 2 ] as a catalyst. This method does not require the use of any ligand system or supplementary additives and is applicable to the preparation of various N -allylhydrazides with good to excellent yields.
使用 2 mol% 的三氟甲磺酸汞 [Hg(OTf) 2 ] 作为催化剂,在非常温和的条件下开发了一种在烯丙基甲硅烷基醚和 N , N - 酰基甲苯基肼之间形成碳 - 氮键的有效方法。该方法不需要使用任何配体系统或辅助添加剂,适用于制备各种N-烯丙基酰肼,收率良好。