“Dry” and “Wet” Green Synthesis of 2,2′‐Disubstituted Quinazolinones

Abstract

An extremely convenient, environmentally benign spirocyclization under either aqueous or solventless conditions, developed for the preparation of spiro[cyclohexane-1,2Ј-(1ЈH)-quinazolin]-4Ј(3ЈH)-one (3), has been utilized to convert α-and β-aminocarboxamides 5a, 5b, 6a-c and 9 and cycloalkanones 2-2b and alkanones 2c-e into 1,4-diazaspiro-[4.5]decan-2-one (10) and cis-, diexo-or diendo-2,2Ј-disub-

Alternative conditions for the synthesis of novel spiro[1,3-N,N-heterocyclic-adamantanes]

“…We have previously described ecofriendly methods for the preparation of quinazolin-4(1H)-ones in aqueous 17 or solvent-free medium from a 2-aminobenzamide (2a) 18 or 2-amino-benzhydrazides (2b and 2c) 19 and a number of aldehydes 20 or ketones. 21 Inspired by the excellent results of the mechanochemical synthesis (e.g., 3a, Table 1, conversion ~ 99%), we decided to extend the ring closure of 1 with the reactions of a number of amides and hydrazides under either aqueous or ball-milling conditions.…”

“…In the light of our work on spirocyclization in/on water [17][18][19] and reported aqueous protocols for the synthesis of nitrogen heterocycles by several research groups, [32][33][34] we were motivated to attempt the preparation of 3a-3h in aqueous medium. For the condensation reactions followed by intramolecular cyclizations, an I 2 /KI catalyst was used.…”

A Simple Green Protocol for the Condensation of Anthranilic Hydrazide with Cyclohexanone and N‐Benzylpiperidinone in Water

“…On the other hand, the condensation of 1 with 1‐benzyl‐piperidin‐4‐one ( 6 ) under the same reaction conditions gave only 2‐amino‐ N ′‐(1‐benzylpiperidin‐4‐ylidene)benzohydrazide ( 7 ) (Scheme ). In contrast with the above hydrazone formation, tetrahydrospiroquinazolinone was obtained on the cyclocondensation of anthranilamide and cyclohexanone at room temperature in either aqueous or solventless medium without the use of any catalyst .…”

5,6-dihydro-[1,2,4]triazolo[1,5-c]quinazolines. Message 4. Spirocompounds with [1,2,4]triazolo[1,5-c]quinazolines moieties. The synthesis and spectral

“…Reactions of [5+1]-cyclocondensation based on interactions of 1,5-binucleophiles with carbonyl compounds (cycloalkanones, 1-R-4-piperidone and others) can serve as an approach for construction of spiro compounds. Thus, the authors used 2-nitrobenzamide [4], 2-aminobenzamide and its derivatives [2,[5][6][7][8], or 1H-benzo[d] [1,3]oxazine-2,4-dione [9] for the synthesis of 3'-R-1'-R-1'Hspiro[cycloalkane-1,2'-quinazoline]-4'(3'H)-ones, oximes of 2-aminoacetophenone [3] for the synthesis of 4'-methyl-1' ,2'-dihydrospiro[cycloalkane-1,2'-quinazoline]-3-oxides, and 2-(aminomethyl)aniline [10,11] for the synthesis of 3' ,4'-dihydro-1'H-spiro[cyclohexane-1,2'-quinazoline]. However, only one publication was devoted to the synthesis of spiro [piperidine-4,5' (6'H)- [1,2,4]triazolo [1,5-c]quinazolines], in which 2-(1H-1,2,4-triazol-5-yl)aniline was used to form the systems mentioned [2].…”