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The involvement of the crepenynate pathway and an ester of the metabolite HO·CH2·[CC]3·CH[graphic omitted]CH·CO2H in the biogenesis of NC·[CC]2·CH[graphic omitted]CH·CO2H (I) has been demonstrated in biosynthetic experiments with L. diemii cultures. The necessary ω-oxidation appears to be possible at both the C18 and the C10 stages. The carbon skeleton of (I) contains C(9)–C(16) of crepenynate.

Bicyclic oxygen-containing substrates have been hydroxylated by Calonectria decora and by Rhizopus nigricans. Poor yields of mono- and di-oxygenated compounds were obtained. Initial attack appears to occur at carbon atoms remote from the original oxygen function.

Examination of the above Dahlia species revealed the presence of 8 polyacetylenic compounds of which the C16 ene-diyn-ene alcohol (XXXII) and its acetate were new. In representatives of the main garden varieties 36 poly-MeCH[graphic omitted]CH·[CC]2·CH[graphic omitted]CH·CH(OH)·CH(OH)·CHCH2(XVIII), MeCH[graphic omitted]CH·[CC]2·[CH[graphic omitted]CH]2·CH(OH)·CH2·CH2OH (XXVIII), MeCH[graphic omitted]CH·[CC]2·[CH[graphic omitted]CH]2·[CH2]4·CH2·OH (XXXII), Me[CC]3·[CHCH]2·CH(OH)·[CH2]3·CHCH2(XXXVI), acetylenes were detected, including the new (XVIII), (XXVIII), and (XXXVI) and their acetates. Seasonal variations of the content were noted. The C17 alcohol (XXXVI) and the C16 alcohol (XXXII) were synthesised; the latter and the corresponding C14 compound by novel routes.

The new polyacetylenes (2S)-Me[CH2]2·[CC]3·CHCH·CH(OH)·CH2·OH, its glucoside and 3-phenyl-lactate and HO·CH2·CHCH·[CC]2·[CH2]2·CO2H, as well as the known acids HO·CH2·CHCH·[CC]2·[CH2]2·CO2H, HO·CH2·CHCH·[CC]2·[CH2]2·CO2H, and (2R)-PhCH2·CH(OH)·CO2H have been detected in extracts from the culture fluids of F. pallida. The natural C13 diol and its cis-isomer have been synthesised from 2,3-O-isopropylidene-D-glyceraldehyde.

The diynol (–)-EtCH(OH)·[CC]2H has been found in Gymnopilus spectabilis, the triynol and triynoic acid Me[CC]3R (R = CH2·OH or CO2H) have been found in Psilocybe merdaria, Kuehneromyces mutabilis, Russula vesca, and Ramaria flava, and the acids H[CC]3·CH2·CH2·CO2H and HO2C·CH[graphic omitted]CH·[CC]2·CH2·CH2·CO2H have been obtained from Serpula lacrymans cultures. The Strophariaceae, Russulaceae, and Gomphaceae families have not been reported previously as polyacetylene producers.

The new mono-ols RCH(OH)·[CC]2·CH[graphic omitted]CH·[graphic omitted] (R = Et or CHCH2) and the triols R[CC]2·CH[graphic omitted]CH·CH(OH)·[CH2]3·CH2·OH [R = EtCH(OH), CH2CH·CH(OH), or HO·CH2·CHCH] have been found in C. pyramidalis L. and C. medium L. (the Canterbury bell) and synthesised. A known mono-ol (III) and a known triol(VII) were also present.

The esters R[CC]2·CH2CH[graphics omitted]CH·[CH2]7·CO2Me{R = Me[CH2]2, MeCC, cis- or trans-MeCHCH, trans-HO·CH2·CHCH, HO·CH2·CC, cis- or trans-MeO2C·CHCH, MeO2C·CC, (EtO)2CH, OHC, or, H2N·OC} were prepared from the Wittig salt Me3Si·CC·CH2·CH2·PPh3I–via ICC·CH2·CH[graphics omitted]CH·[CH2]7·CO2Me; several were specifically labelled [at C(9), C(17), and C(18)]. The Wittig salt offers a general route to 1-ene-4,6-diyne and more highly unsaturated skipped en-yne systems.

The isolation and determination of structure and absolute stereochemistry of the new triol MeCH[graphic omitted]CH·[CC]2·CH(OH)·CH(OH)·CH[graphic omitted]CH·[CH2]2·CH2·OH from Lobelia cardinalis L. and the hybrid Lobelia x vedariensis are described. The corresponding dihydroxy-aldehyde structure is suggested for a minor polyacetylene from the hybrid.

The new polyacetylenes HO2C·[CC]3·CH2·CH2·OH, cis- and trans-Me[CC]2·CHCH·CH2·CH2·OH, [Me[CC]3·CH2·CH2·OH, and (-)-Me[CC]3·CH(OH)·CH2·OH, as well as the known diol HO·CH2·CH2·[CC]2·CH2·CH2·OH, also new as a fungal metabolite, have been detected in extracts from the culture fluids of C. peronata and also synthesised.

Biosynthetic experiments with a number of differently 14C-labelled hypothetical precursors have shown that cellocidin (acetylenedicarboxamide) is an offshoot of the Krebs cycle and arises in Streptomyces SF-536 cultures directly from carbon atoms 2–5 of 2-oxoglutarate.

Three new C14 polyacetylenes, the epoxy-alcohol (R = CH2·OH) and aldehyde (R = CHO) RCHCH·[CC]2·CH([graphic omitted]H·[graphic omitted], and the triol, HO·CH2·CHCH·[CC]2·CH(OH)·CH(OH)·[graphic omitted], as well as the known alcohol, HO·CH2·CHCH·[CC]2·CHCH·[graphic omitted] have been detected in extracts from Trachelium caeruleum L. A partial structure for another constituent, a C14 enediynene diol, is proposed. The two epoxides and the triol have been synthesised and their stereochemistry partly elucidated.

Specifically labelled methyl crepenynate and oleate have been synthesised from the C9 phosphoranes, Me[CH2]4·CC·CH2·CHPPh3 and Me[CH2]7·CHPPh3, respectively, and the C9 aldehyde ester, OCH·[CH2]7·CO2Me; methyl linoleate has been obtained by partial hydrogenation of the crepenynate. Carbon-14 was introduced into the C18 esters via the [9-14C]- and [1,9-14C]-aldehyde esters, and tritium via a reaction of the phosphoranes with tritiated methanol. Several routes to the labelled C9 aldehyde ester are described.

The new acetylenic nitrile NC·CC·CH[graphic omitted] has been isolated from the culture fluids of L. glaucocana. It is accompanied by four known acetylenic acids already found to be produced by L. diemii.