Intracellular pH and Inorganic Phosphate Effects on Skeletal Muscle Force

121 used as stubstituents on Ci and C2; namely H, CH 3 , C 2 H 5 , and CeHs. They are differentiated to have approximately 1, 2, 3, and 5 A in their diameters as spherical models. For simplified discussion, we consider that 2 has bulkier substituents on Ci than on C2. Thus the C2 site will be more reactive than the Ci site for dimerization. In this occasion discussion will be rather limited to the bulkiness of substituents on C2. In cases where substituents are two C6H5 or one CgHs and one H, monomer dianions are formed (Scheme 1). Dimerization of the radical anion occurs in cases where the substituents are two hydrogens or one H and one CH3 (Scheme 2). In cases where the substituents are two CH3, disproportionate occurs (Scheme 3). Therefore bulkiness of the substituents may control the progress of the reaction. Two alkyl groups are large in size for dimer-ization, and small for dianion formation , and may be suitable for disproportionation. For dispropor-tionation reaction, the substituent must have a hydrogen to be abstracted. One CH3 on C2 of la is substituted by C2H5 in order to investigate which hydrogen in two substituents, either CH3 or C2H5, is easily abstracted. From analyses of a mixture of the products, it is concluded that the hydrogen-leaving power is about ten times stronger in CH 3 than in C 2 H 5. Acknowledgement The authors wish to thank Mr. K. Kushida and A. Ono (Varian Instruments, Ltd.) for their kindness in measuring several 2D CH COSY spectra at 100.6 MHz. 8) The charge calculation was followed by using an empirical equation proposed by Fraenkel et al.[9] and proportional factors presented by Schaefer et al.[10,ll] 9) G.Fraenkel, et al.,