A Practical Entry to the Crambescidin Family of Guanidine Alkaloids. Enantioselective Total Syntheses of Ptilomycalin A, Crambescidin 657 and Its Methyl Ester (Neofolitispates 2), and Crambescidin 800

Abstract

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Guanidine alkaloid analogs as inhibitors of HIV-1 Nef interactions with p53, actin, and p56 lck

“…A library containing the natural products ptilomycalin A, batzelladine F, and 46 batzelladine-and crambescidin-based analogs (33,37,38) were initially screened by competition ELISA (Fig. 2 and Figs.…”

“…Batzelladine and crambescidin analogs were synthesized as described (33,(35)(36)(37)(38). Each compound was stored at Ϫ20°C at an average concentration of 10 mg͞ml in DMSO.…”

Crystallographic and NMR studies of antiinfective tricyclic guanidine alkaloids from the sponge Monanchora unguifera

“…9 The intriguing molecular structures and their significant biological activities have attracted considerable synthetic interest. The synthesis of a number of guanidine alkaloids have been reported, including ptilocaulin, 1,19 crambescins A, B, C1, and C2, 1 ptilomycalin A, crambescidins 657, 800, 9,20 and batzelladines D, 21 E, 22 F. 23 As part of our continuing efforts to identify biologically active marine natural products for development as antiinfective agents, we evaluated the highly active ethanol extract of the marine sponge Monanchora unguifera (de Laubenfels, 1953) (Order Poecilosclerida: Family Crambeidae) with the guidance of bioassays and obtained 1,8a;8b,3a-didehydro-8β-hydroxyptilocaulin (1) and its stereoisomer, new 1,8a;8b,3a-didehydro-8α-hydroxyptilocaulin (2) and mirabilin B (3). Barrow et al, and Patil et al reported the isolation of mirabilin B (3) from the sponge Arenochalina mirabilis and Batzella sp.…”

Synthesis, applications and mechanistic investigations of C2 symmetric guanidinium salts

“…The deep red solution that formed was then stirred at -60 ºC for 1 h. The reaction was cooled (-78 ºC) and (R)-3-((tert-butyldimethylsilyl)oxy)-1-iodobutane 16 (8.26 g, 26.3 mmol) in THF (42 mL) was added and the reaction warmed to rt by removal of the cooling bath followed by stirring overnight. Water (90 mL) was added and the solution was separated and the aqueous fraction extracted with dichloromethane (3 × 50 mL), the combined extracts dried (MgSO 4 ) and concentrated by rotary evaporation to approximately 50 mL.…”