A compound according to Formula IA and IB, reversibly convertible under photochromic and electrochromic conditions between a ring-open isomer A and a ring-closed isomer B is provided. For substitutent groups, Z is N, O or S; each R.sub.1 is independently selected from the group consisting of H, or halo; each R.sub.2 is independently selected from the group consisting of H, halo, a polymer backbone, alkyl or aryl; or, when both R.sub.2 together form CHCH and form part of a polymer backbone; each R.sub.3 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl; each R.sub.4 is aryl; and each R.sub.5 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl.

##STR00001##

A compound according to Formula IA and IB, reversibly convertible under photochromic and electrochromic conditions between a ring-open isomer A and a ring-closed isomer B is provided. For substitutent groups, Z is N, O or S; each R.sub.1 is independently selected from the group consisting of H, or halo; each R.sub.2 is independently selected from the group consisting of H, halo, a polymer backbone, alkyl or aryl; or, when both R.sub.2 together form CHCH and form part of a polymer backbone; each R.sub.3 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl; each R.sub.4 is aryl; and each R.sub.5 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl.

##STR00001##

An object is to provide a method for producing a compound which is useful as a synthetic intermediate for an active pharmaceutical ingredient of an antidiabetic drug or the like in an industrially inexpensive and efficient manner, and the present invention can achieve the object by reducing a compound (2) represented by the following formula (2): ##STR00001## wherein R.sub.1, Ar, n and X are as mentioned herein in the presence of a titanium compound by using a reducing agent to produce a compound (1) represented by the following formula (1): ##STR00002## wherein R.sub.1, Ar and n are the same as defined above.

An object is to provide a method for producing a compound which is useful as a synthetic intermediate for an active pharmaceutical ingredient of an antidiabetic drug or the like in an industrially inexpensive and efficient manner, and the present invention can achieve the object by reducing a compound (2) represented by the following formula (2): ##STR00001## wherein R.sub.1, Ar, n and X are as mentioned herein in the presence of a titanium compound by using a reducing agent to produce a compound (1) represented by the following formula (1): ##STR00002## wherein R.sub.1, Ar and n are the same as defined above.

Provided herein are processes for the preparation of 2-thiophenecarbonyl chloride, which is useful, for example, in the preparation of 3,5-disubstituted-1,2,4-oxadiazoles, such as tioxazafen (3-phenyl-5-(2-thienyl)-1,2,4-oxadiazole).

Provided herein are processes for the preparation of 2-thiophenecarbonyl chloride, which is useful, for example, in the preparation of 3,5-disubstituted-1,2,4-oxadiazoles, such as tioxazafen (3-phenyl-5-(2-thienyl)-1,2,4-oxadiazole).

A compound according to Formula IA and IB, reversibly convertible under photochromic and electrochromic conditions between a ring-open isomer A and a ring-closed isomer B is provided. For substitutent groups, Z is N, O or S; each R.sub.1 is independently selected from the group consisting of H, or halo; each R.sub.2 is independently selected from the group consisting of H, halo, a polymer backbone, alkyl or aryl; or, when both R.sub.2 together form CHCH and form part of a polymer backbone; each R.sub.3 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl; each R.sub.4 is aryl; and each R.sub.5 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl.

##STR00001##

A compound according to Formula IA and IB, reversibly convertible under photochromic and electrochromic conditions between a ring-open isomer A and a ring-closed isomer B is provided. For substitutent groups, Z is N, O or S; each R.sub.1 is independently selected from the group consisting of H, or halo; each R.sub.2 is independently selected from the group consisting of H, halo, a polymer backbone, alkyl or aryl; or, when both R.sub.2 together form CHCH and form part of a polymer backbone; each R.sub.3 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl; each R.sub.4 is aryl; and each R.sub.5 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl.

##STR00001##

Compounds of formula I ##STR00001##
their use in liquid-crystalline media, for example, for the phase shifting of microwaves for tunable phased-array antennae, and their use for high-frequency components, in particular antennae, especially for the gigahertz range.

Compounds of formula I ##STR00001##
their use in liquid-crystalline media, for example, for the phase shifting of microwaves for tunable phased-array antennae, and their use for high-frequency components, in particular antennae, especially for the gigahertz range.