New chondropsin macrolide lactams from marine sponges in the genus Ircinia

Two new polyketide-derived macrolide lactams, identified as 73-deoxychondropsin A (2) and chondropsin C (3), have been isolated from two different collections of marine sponges which belong to the genus Ircinia. An Australian collection of Ircinia ramosa provided 73-deoxychondropsin A (2), while samples of Ircinia sp. collected in the Philippines yielded chondropsin C (3). The structures of 2 and 3 were assigned by interpretation of their spectral data.