Unique substituted 3-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]benzimidazole-1-carboxamides generated by Ugi 3CC using bifunctional starting material

An Efficient Ugi‐Azide Four‐Component Approach for the Preparation of Novel 1‐(1H‐tetrazol‐5‐yl)‐10‐chloro‐1,2,3,4‐tetrahydropyrazino[1,2‐a] Indoles

“…In continuation of our previous approaches to the synthesis of pyrazino[1,2‐ a ] benzimidazoles , indoloketopiperazines , 2,6‐diketopiperazines , N , N′ ‐disubstituted piperazines , 1‐(1 H ‐tetrazol‐5‐yl)‐1,2,3,4‐tetrahydropyrrolo[1,2‐ a ] pyrazine derivatives , tetazoles , and bis‐tetrazolopiperazines , herein, we disclose our new synthetic method to novel 1‐(1 H ‐tetrazol‐5‐yl)‐10‐chloro‐1,2,3,4‐tetrahydropyrazino[1,2‐ a ] indoles derivatives (Fig. ).…”

Synthesis of Various N‐heterocycles Using the Ugi Four‐Center Three‐Component Reaction

“…2‐(2‐Formyl‐1 H ‐benzimidazol‐1‐yl)acetic acid as a bifunctional formyl‐acid was utilized along with primary amines and alkyl isocyanides under U‐4 C‐3CR conditions for the one‐pot synthesis of a series of novel 3‐oxo‐1,2,3,4‐tetrahydropyrazino[1,2‐ a ]benzimidazole‐1‐carboxamides 32 . This method offers several advantages such as easy experimental work‐up procedure and moderates to high yields (Scheme ) …”

One‐pot synthesis of benzimidazole‐pyrazines and their anticancer activities

“…The Ugi reaction, as a typical MCR, has been widely investigated in organic chemistry for drug discovery since 1959 . Ghandi et al reported the synthesis of compound I as an example of an important type of pharmacologically active compound through an Ugi three‐component condensation (Ugi‐3CC) in high yields under simple work‐up procedures . Compound II was constructed via a Ugi/deprotection/cyclization (UDC) strategy, followed by a nucleophilic substitution reaction in good yields ; this compound was also reported to be obtained via an intramolecular Goldberg reaction in one step using CuI as a catalyst .…”