Citrus‐Carotenoids. Synthesis of (3R)‐β‐Citraurin, (3R)‐β‐Citraurol and (3R)‐β‐Citraurinene; Determination of the Configuration of Citrus‐Carotenoids (3R)‐β‐Citraurin, (3R)‐β‐citraurol and (3R)‐β‐citraurinene were prepared starting from (3R)‐3‐acetoxy‐β‐ionone. Comparison of the chiroptical data of β‐citraurin from orange peels with those of the synthetic compound confirmed the 3R‐configuration of the natural pigment.

For many applications in cursive script recognition the vocabulary is restricted to a small and fixed set of words. In a recognition approach such as Hidden Markov Models, for each of these words a model is constructed and trained. In the recognition task an unknown pattern is matched with all of these models to find the most likely class. In this paper, we describe a method for reducing the size of vocabulary depending on the actual input. In contrast to many other techniques, our approach is not using any topological features. The reduction system is directly based on the quantized feature vectors which are used as input for the HMMs. Thus very little additional work is required for lexicon reduction. The proposed approach was successfully tested on two different systems with small lexicons. In both cases, the lexicon could be reduced to 25% of its original size without increasing an the error rate.

Synthesis of Apocarotenoides with a Shifted Methyl Group; Structure Elucidation of Citrus‐Carotenoides With regard to the investigation of the biosynthesis of the C30‐carotenoids in citrus fruits apocarotenoids with a methyl group shifted by one position (diapocarotenoids) were synthesized. Characteristical differences, especially in the 270‐MHz‐1H‐NMR. spectra between the apo‐ and the diapocarotenoids are reported. The comparison of the natural pigments with the synthetic compounds proves that the natural products belong to the apocarotenoids as has been postulated earlier.

Aus (3R)‐3‐Acetoxy‐β‐ionon wird durch alkalische Hydrolyse das Hydroxy‐Derivat (I) (90% Ausb.) dargestellt und mit dem Grignard‐Reagenz (II) zu dem Alkohol (III) umgesetzt, der in das Phosphoniumsalz (IV) übergeführt wird.

Um eindeutige Strukturbeweise sowie biogenetische Hinweise für die Cw‐Apocarotinoide der Citrusfrüchte zu erhalten, werden verschiedene Carotinoide mit "versetzter" Methylgruppe (Diapocarotinoide) synthetisiert und deren Eigenschaften sowohl mit den synthetischen Isomeren ohne "versetzte" Methylgruppe (Apocarotinoide) als auch mit natürlichen Pigmenten aus Orangen.schalen verglichen.