Multicomponent Coupling Cyclization Access to Cinnolines via in Situ Generated Diazene with Arynes, and α-Bromo Ketones

Abstract

A transition-metal-free multicomponent coupling cyclization reaction was explored involving arynes, tosylhydrazine, and α-bromo ketones. The reaction proceeds via a formal [2 + 2 + 2] cycloaddition, giving access to cinnoline derivatives in moderate yields under mild conditions. Three chemical bonds were formed-two C-N bonds and one C-C bond-in a single step.

BF3-Etherate-Promoted Cascade Reaction of 2-Alkynylanilines with Nitriles: One-Pot Assembly of 4-Amido-Cinnolines

“…In the case of the Ritcher cinnoline synthesis, the reaction proceeds via an intramolecular cyclization of the ortho -alkyne functionality in the presence of a hydrohalic acid, such as HBr or HCl and NaNO 2 , to afford a mixture of halocinnolines and cinnolinones . However, restricted substrate scope, activated alkynes, and strongly acidic conditions limit their application. , Aiming to improve the efficiency of substrate scope and mild reaction conditions, recently a few methodologies based on metals and metal-free strategies have been developed for the synthesis of cinnolines. Although these methods provide fruitful access to cinnoline derivatives, hitherto there has been no literature precedent for the straightforward construction of 4-amido/amino-cinnolines. , …”

Sulfonyl Hydrazides in Organic Synthesis: A Review of Recent Studies

“…As shown in Scheme , our review is based on ten categories: (1) sulfonyl radiacls; (2) thiosulfonates; (3) ArS . radicals; (4) sulfur‐centered anions; (5/6) metallo‐organic compounds with or without sulfonyl moiety; (7/8) electrophilic RSX or RS‐DBU intermediates; (9) nucleophilic hydrazines; (10) sulfonyl hydrazides as diazene or sulfinic acid surrogate. In order to illustrate the mechanism within the schemes, where relevant, it is given in a gray box.…”

Recent advances in the synthesis of five‐ and six‐membered heterocycles as bioactive skeleton: A concise overview

“…It involved the treatment of α‐bromo ketone ( 266 ) with ortho‐substituted ‐(trimethylsilyl) aryl triflate ( 264 ) in the presence of tosylhydrazine ( 265 ) and CsF in acetonitrile at 90 °C to afford the cinnolene derivatives in excellent yields (Scheme 52). [98] The yield of the products was greatly affected by the electron‐neutral or electron‐donating substituents at α ‐bromo ketones and phenyl substituents.…”