Glomerin and Homoglomerin

Quinazoline alkaloids are known as biologically active compounds. Arborine inhibits the peripheral action of acetylcholine and induces a fall in blood pressure. Febrifugine is an anti-malarial agent and vasicine acts as a uterine stimulant. Glomerin and homoglomerin are alkaloids of the defensive system in some organisms (e.g., in the glomerid millipede). 

A number of nemertine worms, such as Amphiporus or Nereis, produce alkaloids such as 2,3-bipyridyl, anabaseine, nemertelline, or nereis-toxin, which are toxic to predators such as crayfish 4,17,28,230,226,). Arthropod-made alkaloids include glomerine and homoglomerine in Glom-erus 215), adaline in Adalia 227), coccinelline, euphococcinine, and derivatives in Coccinella, Epilachna, and other coccinellid beetles 28,226,227,235), and stenusine in Stenus 215), which are considered to be antipredatory compounds 4,17,28,494-496). 

Glomerin and homoglomerin formed in Glomeris marginata are constituents of defense secretions (E 5.1). 

Two similar syntheses have been reported by Ziegler and co-workers (487) and Kametani et al. (488,489). Reaction of N-methylisatic anhydride (584) with thioacetamide afforded glomerin (60) in 58% yield (487). The other synthetic route is as follows The sulfinamide (585), prepared from N-methylanthranilic anhydride and thionyl chloride, was treated with acetamide and propionamide to afford glomerin (60) and homoglomerin (61), respectively (Scheme 72) (488,489). 

It has been demonstrated that [carboxy- C]anthranilic acid is also a precursor of the animal alkaloids glomerin (2) and homoglomerin 171). 

Quinazoline alkaloids contain more than 100 compounds. They have been isolated from animal and plant sources. The plant family Rutaceae is especially rich in these alkaloids. Typical quinazoline alkaloids include, for example, arborine, glomerin, homoglomerin, glycerine, glycosminine, febrifugine and... 

Treatment of the sulfinamide anhydride, prepared from anthranilic acid and thionyl chloride, with carboxamides and thiocarboxamides 1 affords quinazolin-4(3//)-ones 2. Thiocarbox-amides, being much more easily dissolved than carboxamides in nonprotic solvents such as benzene, are more suitable as starting materials. This approach has been used by Kametani et al. in the synthesis of the quinazoline alkaloids glomerine, homoglomerine, chrysoginc, and glycosminine. " ... 

Chakraborty et al. (26) synthesized 1 by cyclization of the < -acyl-aminobenzamide 13 with diphosphorus pentoxide. Kametani et al. have developed a one-step synthesis of quinazolinone derivatives by condensation of sul-phinamide anhydrides generated from anthranilic acids and thionyl chloride with amides (27,28), imines (29,30), or thioamides (31). This reaction was applied to the synthesis of 1 (28,31,32), glycosminine (6) (28,31), glomerin (2) (27,31), homoglomerin (27), glycerine (3) (27), chrysogine (7) (27), and other quinazoline alkaloids (Scheme 1). 

Kametani, T., C. V. Loc, T. Higa, M. Ihara, and K. Fukumoto Studies on the Syntheses of Heterocyclic Compounds. Part 724. Total Syntheses of the Quinazolinone Alkaloids Glycorine, Glomerine, Homoglomerine, Crysogine, and Euxylophoricines A and C. J. Chem. Soc. Perkin Trans. I 1977, 2347. 

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