66016-16-8

An optically inactive cyclobutanecarboxylic acid derivative of the general formula STR1 wherein R1 is a hydrogen atom or a straight or branched chain alkyl group having 1-14 carbon atoms, R2 is a straight or branched chain alkyl grou

The preparation of sixteen dimethylene linked compounds is described heptane ring>, and a comparison is made between the transition temperatures of these compounds and those of the corresponding esters.This comparison once again highlights the fact that the cyclobutane ring should be regarded, in terms of its ability to promote nematic thermal stability, as a "chain stiffener rather than as a ring system.A comparison is also made of the nematic thermal stabilities of the trans-cyclobutane and the spiroheptane systems and of the trans-cyclohexane and the spiroundecane systems.

A number of esters of structure (I) incorporating the cyclobutane, spiroheptane, or dispirodecane rings has been prepared using a diethyl malonate synthesis.Strict comparison of the liquid crystal behaviour amongst the three classes containing a terminal cyano-substituent was not possible because both the cyclobutanes and dispirodecanes are mixtures of cis- and trans-isomers; the spiroheptanes are racemic systems.Using preparative hplc, it was however possible to isolate the pure cis- and trans-isomers of two of the cyano-substituted cyclobutane esters (I; R = alkyl, -X- = --, Y = CN).From the physical data and the results for the corresponding spiroheptane esters, conclusions regarding the effects of these ring systems on liquid crystal behaviour were obtained.The pure cis- and trans-isomers of the cyclobutane ester (I, R = C3H7, -X- = --, Y = CN) have been assessed for the trends in both order parameter and viscosity with temperature; the results support the idea that idea that the trans-cyclobutane ring adopts a more planar conformation at higher temperatures.Keywords: cyclobutane- and related spiro-systems, cis-/trans-isomerism, order parameter, briefringence, viscosity, structure/property relations.

Several esters of norethisterone (17α-ethynyl-17β-hydroxyestr-4-en-3-one) with carboxylic acids containing a cyclopropyl or cyclobutyl ring have been synthesized and the stereochemistries of the side-chains determined.

Novel C15 cyclobutyl analogs or derivatives of prostaglandins of the E-, A- and F-classes are useful modifiers of smooth muscle activity. The compounds have valuable pharmacological properties such as platelet antiaggregating agents, gastric antisecretory agents and brochodilating agents.

Analogues of PGE1 having the structural formula, STR1 in which J is R-hydroxymethylene or S-hydroxymethylene; R1 is hydrogen; R2 is hydrogen or together with R4 is a methylene chain of 2 to 3 carbon atoms such that a cycloalkyl of 5 to 6 carbon atoms inclusive is formed; R3 is hydrogen or methyl, or together with R4 is a methylene or a lower alkylated methylene chain of 2 to 5 carbon atoms such that a cycloalkyl or a lower alkylated cycloalkyl of 4 to 7 carbon atoms inclusive is formed, or together with R4 is bicycloalkyl or bicycloalkenyl moiety having the formula: STR2 SUCH THAT A BICYCLOALKYL OR BICYCLOALKENYL COMPOUND IS FORMED, WHEREIN M AND N ARE INTEGERS HAVING A VALUE FROM 0 TO 3, P IS AN INTEGER HAVING A VALUE FROM 0 TO 4 AND Q IS AN INTEGER HAVING A VALUE OF FROM 1 TO 4 AND WHEREIN THE DOUBLE BOND OF SUCH BICYCLOALKENYL IS IN THE M, N, P, OR Q BRIDGE; R4 is hydrogen or methyl or together with R2 or R3 forms a cycloalkyl or bicycloalkyl or bicycloalkenyl as defined above, or together with R5 is a methylene chain of 3 to 5 carbon atoms such that a cycloalkyl of 4 to 6 carbon atoms inclusive is formed; R5 is selected from the group consisting of hydrogen, straight-chain alkyl having from 1 to 3 carbon atoms or together with R4 forms a cycloalkyl as defined above; and R6 is hydrogen or straight-chain alkyl having from 1 to 3 carbon atoms are disclosed. Pge1 ester analogues of the above formula, limited to the structures wherein two of R2, R3 R4 and R5 form a cycloalkyl, lower alkylated cycloalkyl, bicycloalkyl or bicycloalkenyl are also disclosed. The prostaglandin analogues selectively produce bronchodilation and decrease gastric secretion in vivo. Methods of preparing the analogues and starting materials required in the synthesis of the analogues are also disclosed.

Antiinflammatory and analgesic activities of 3 substituted cyclobutanecarboxylic acids are pointed out and their structure-activity relationship examined according to the Hansch method. This analysis shows the influence of the steric and lipophilic parameters and this quantitative basis let us realize the synthesis of two acids, the analgesic acitivities of which are very much improved. Attempted quantitative correlations between physiochemical parameters and antiinflammatory activity were unsuccessful. This is imputable to a too imprecise representation of the steric effect which plays a primordial part in this kind of activity.