The application relates to a process for the preparation of a compound of formula (II) by cyclisation of a polyene of formula (I), and to an intermediate of formula (III). The obtained compounds are useful intermediates in the preparation of specific isoprenoids, preferably in the production of vitamin A and derivatives of vitamin A.

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The present invention relates to a new dehydrogenation process of specific compounds.

The present invention provides methods and compositions for treating atopic dermatitis by cyclohexenone compounds.

The present invention provides methods and compositions for treating atopic dermatitis by cyclohexenone compounds.

A method for preparing dehydro-cyclofarnesal from dehydro-farnesal by cyclization in the presence of an acid may include the dehydro-farnesal being obtained from the farnesal by dehydrogenation and may further includes the cyclization being carried out in the presence of an acid selected from Lewis acids, Bronstedt acids, and zeolites. The synthesis of vitamin A using this method further includes the conversion of dehydro-cyclofarnesal into vitamin A.

A method for preparing dehydro-cyclofarnesal from dehydro-farnesal by cyclization in the presence of an acid may include the dehydro-farnesal being obtained from the farnesal by dehydrogenation and may further includes the cyclization being carried out in the presence of an acid selected from Lewis acids, Bronstedt acids, and zeolites. The synthesis of vitamin A using this method further includes the conversion of dehydro-cyclofarnesal into vitamin A.

The invention provides compounds of formula (I): or a salt thereof as described herein. The invention also provides pharmaceutical compositions comprising a compound of formula (I), processes for preparing compounds of formula (I), intermediates useful for preparing compounds of formula I and therapeutic methods for treating a Retroviridae viral infection including an infection caused by the HIV virus. ##STR00001##

The invention provides compounds of formula (I): or a salt thereof as described herein. The invention also provides pharmaceutical compositions comprising a compound of formula (I), processes for preparing compounds of formula (I), intermediates useful for preparing compounds of formula I and therapeutic methods for treating a Retroviridae viral infection including an infection caused by the HIV virus. ##STR00001##

The present invention relates to a new dehydrogenation process of specific compounds.

The present invention relates to a new dehydrogenation process of specific compounds.