Pyrimidine, Purine, and Related Alkaloids

3-Methyl-2 -deoxycytidine (437) and 3-methyl-2 -deoxyuridine (438) were isolated from the Swedish sponge Geodia baretti. Compound 437 exhibits strong contractile activity in the isolated guinea pig ileum assay, whereas 438 had no effect on contractions (356). Thymidine-5 -carboxylic acid (439) and 2 -deoxyuridine-5 -carboxylic acid (440), which were previously known only as synthetic products, were found in extracts of the ascidian Aplidium fuscum of the East Pyrenean coast (357). 

2-Iminomethyl-3-methyl-6-aminomethyl-9//-purine (441) was isolated from the sea anemone Sagartia troglodytes collected in the Bay of Naples. The structure of 441 was determined by X-ray analysis. The synthetic 2,6-diaminopurine (DAP) shows a wide variety of biological activities such as inhibition of the growth of tumors, viruses, plants, or bacteria, whereas the trimethyl derivative (441) shows considerably less inhibitory capacity than DAP (358). A new purine, 1,3,7-trimethyl-guanine (442), was isolated 

The northeast Pacific bryozoans Phidolopora pacifica contained two nitrophenols, desmethylphidolopin (448) and 3-nitro-4-hydroxybenzyl alcohol (449) (365). Desmethylphidolopin (448) showed antimicrobial activity. 2-Amino-6-[(r/ ,2 5)-l, 2 -dihydroxypropyl]-3-methyl pterin-4-one (450) was isolated from the anthozoan Astroides calycularis collected in the Bay of Naples and exhibited cell growth-inhibiting activity (366). The structure of leucettidine, a pteridine derivative found in Leucetta microra- 

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