A convenient route to thieno [3,2-b]thiophene-2-carboxyaldehyde (1) for the synthesis of new 5-n-decylthieno[3, 2-b]thiophene-2-carboxylic acid (10) is described. A class of novel supramolecular liquid-crystalline complexes are formed starting from 10 or 5-n-decylthiophene-2-carboxylic acids and stilbazoles, through intermolecular hydrogen bonding.

4‐Arylpyridines 5 that contain electron‐withdrawing groups such as nitrile, methyl ester, fluoride, and trifluoromethyl on the benzene ring were synthesized in moderate yields (29‐63%) by reaction of mixed copper, zinc aryl organometallics 1 with various 1‐(ethoxycarbonyi)pyridinium chlorides 2 followed by o‐chloranil oxidization under reflux in toluene.

X‐ray structures of trans‐2‐dimethylamino‐5‐phenyl‐2H‐1,3,2‐oxazaphosphorinane‐2‐oxide, 5b, and trans‐2‐dimethylamino‐6‐phenyl‐2H‐1,3,2‐oxazaphosphorinane‐2‐oxide, 6c, have been determined. These two compounds have been prepared in a straightforward manner by a reaction of cyclization of Mc2NP(O)Cl2 with the corresponding 3‐amino‐2‐phenylpropanol and 3‐amino‐1‐phenylpropanol, respectively, to produce (5b, 6b) and (5c, 6c), and were separated into pure forms by chromatography. Crystal data of 5b: space group Pccn, a = 10.675(5), b = 31.685(9), c = 7.217(3) Å, R = 0.065 for 1040 reflections. Crystal data of 6c: space group P‐1, a = 9.803(6), b = 12.455(5), c = 12.690(2) Å, α = 114.11(2), β = 80.88(2), γ = 111.64(4)°, R = 0.035 for 3534 reflections. For the pair 5b and 6b, the slowly‐migrating 5b is trans (Ph and P = O group trans) with the configuration of 2RS, 5RS, hence 6b is the cis isomer. For the pair 5c and 6c, the slowly migrating 6c is trans with the configuration of 2RS, 6SR; hence 5c is the cis isomer. In both X‐ray structures the 1,3,2‐oxazaphosphorinane rings are chair‐like with the P‐end essentially flattened. With a conformationally demanding 5‐phenyl substituent, 5b has an axial Me2N whereas with also a conformationally demanding 6‐phenyl substituent, 6c has an equatorial Me2N. For 6c, the exocyclic P‐N bond has partial double bond character: the geometry about exocyclic N is planar. On the other hand, for 5b, the geometry about exocyclic N deviates considerably from planarity, the sum of the angles around N being 343.3°. In the crystalline state, the two crystallographically independent molecules of 6c are linked together in a hydrogen‐bonded system involving the water molecule.