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Evidences of some unusual behaviours of 2‐aminothiazol and 2‐aminobenzothiazol in reactions with formaldehyde and glyoxal
Author(s) -
Ghandi Mehdi,
Olyaei Abolfazl
Publication year - 2007
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570440207
Subject(s) - chemistry , glyoxal , formaldehyde , acetonitrile , imidazolidine , aqueous solution , medicinal chemistry , methanol , condensation reaction , organic chemistry , catalysis
In contrast to the previously reported acid‐catalyzed reaction of 2‐aminothiazole with aqueous formaldehyde in water at 0‐5 °C which afforded N,N ′‐bis(2‐thiazolyl)methanediamine ( 4 ), 5,5′‐methylenebis(2‐aminothiazole) ( 5 ) is obtained as the unique product under reflux conditions. Reaction of 2‐aminobenzothiazole with aqueous formaldehyde in acetonitrile at 0‐5 °C or under reflux conditions produces (2‐benzothiazolylamino)methanol ( 6 ) or N,N ′‐bis(2‐benzothiazolyl)methanediamine ( 7 ), respectively. Heating monoamine 6 in acetonitrile remarkably yields the symmetric diamine 7 . While cyclocondensation of 2‐aminothiazole with aqueous glyoxal in acetonitrile gives 3,4,8,9‐tetrahydroxy‐7,10‐bis(2‐thiazolyl)‐2,5‐dioxa‐7,10‐diazabicyclo[4.4.0]decane ( 8 ), reaction of 2‐aminobenzothiazole with glyoxal fails to produce similar results; In the presence of aqueous formaldehyde, although the former reaction leads to the formation of 4‐hydroxy‐5‐(thiazolylamino)‐1,3‐bis(2‐thiazolyl)imidazolidine ( 9 ), utilization of 2‐aminobenzothiazole gives 4,5‐dihydroxy‐1,3‐bis(2‐benzothiazolyl)imidazolidine ( 10 ). Condensation of either 6 or 7 with aqueous glyoxal affords compound 10 . Details of the reactions will be discussed in this presentation.