✍ Scribed by Mehdi Ghandi; Abolfazl Olyaei
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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.
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Institute of Organic Chemistry, Karl-Franzens University of Graz, Heinrichstr. 28, A-8010 Graz, Austria
A series of chemically altered coals was investigated in the reaction with methanol and hydrogen in the presence of ZnClz as a catalyst. Significant beneficial effects were observed when high-rank coals were altered by reductive and reductively methylating pretreatments. The behaviour of altered low