Bacterial Carotenoids. XVIII. Aryl-carotenes from Phaeobium.

Abstract
The carotenoids of some photosynthetic, brown bacteria have been studied. The diaryl-carotene isorenieratene (= leprotene)(I) is a major carotene. The natural occurrence of [beta]-isorenieratene (n) has been demonstrated for the first time. Chloro-bactene (VI), the characteristic aryl-carotene of photosynthetic green bacteria, and [beta]-carotene (III) are trace carotenoids.