NOTES
2822
Vol. 70
methylphthalimide. This compound was first prepared by Sachs' by the hydrolysis of N-browhere De is an ef€ective dielectric constant, N momethylphthalimide. It was later prepared by is Avogadro's number, M the molecular weight Sachs2 from formaldehyde and phthalimide in of the linear molecular unit of the structure and sealed tubes and by Buca from the same reactants a t atmospheric pressure. The melting. points rep is the density of the structure, regarded as a three-dimensional network with L the average ported by these authors were 141-142 , 139-140' distance between net points. Since electrostatic and 137-141°, respectively. Buc also reported interactions between the charges of neighboring that the melting point is not improved by crystalchain segments are neglected and other gross lization from ethanol. We attempted to eliminate the impurities by approximations have been employed in its deriadding about 1 g. of fuller's earth per 100 ml. of vation, Eq. (1) is intended to provide no more than an estimate of the order of magnitude of AE. solution in BUC'Sprocedure. This yielded a prodThe elastic modulus of muscle1 is of the order uct melting a t 14e145' whicb was, however, still of magnitude 10" dynes/sq. cm. In order to not pure. A product of high purity melting a t 149.5' was produce a change of this order of magnitude by 'ng the structural units, we estimate from finally obtained through an unstable, previously Eq. 1) a magnitude of n of the order of 100, with unreported complex formed from N-hydroxythe rough assignments of value P = 1, M = lo6, methylphthalimide and one mole of pyridine. Chloro-, bromo- and iodomethylphthalimides L = 104A, De = 100 to the other parameters. The values of L and M are those determined for were prepared from the pure compound and the the myosin or actomyosin molecule in solution, appropriate halogen acid. In all cases the prodand De is assumed to be of the order of magnitude ucts had higher melting points than those previof the dielectric constant of water. The esti- ously reported. Procedure.-A solution obtained by warming 17.7 g. mated number of charges would require phosN-hydroxymethylphthalimidea in 30 ml. of pure phorylation sites situated a t intervals of 100 A. of pyridine was filtered, if necessary, and left to crystallize. along the myosin or actomyosin molecule. This If crystallization did not occur, seed crystals were obtained value is not inconsistent with the hydroxy amino by placing a few drops of the solution in a desiccator over sulfuric acid. As soon as the first crystals appeared, they acid content of myosin. added to the solution. The new compound crystalThe observation of Needham' that the flow were lized in long, bright needles which after cooling in an birefringence of myosin solutions is diminished ice-bath were filtered with suction. by the addition of ATP seems a t first to be in To determine the pyridine the crystals were dried briefly contradiction with our hypothesis. However, on a porous plate over calcium chloride. A weighed was then dried in vacuum over sulfuric acid. it seems that the effect was observed under condi- sample The crystals gradually lost their brightness and came to tions leading to the dissociation of actomyosin constant weight after twenty-four hours. into actin and myosin, according to St. Gyorgi.6 Anal. Calcd. for CeHtOaNCbHsN: pyridine, 30.58. We have deliberately avoided placing undue Found: pyridine, 30.68. The residue melts at 148.5-149 '. One crystallization emphasis on hypothetical structural details of acetone brings the m. p. to 149.5'. muscle and on the detailed analogy between the from Anal. Calcd. for C&03N: N,7.91. Found: N, 7.88. elastic properties of muscle and elastomers. The halogenomethylphthalimides were prepared esThe essential qualitative aspects of our sugges- sentially according to Gabriel,' heating at 50" for one hour tions, (a) change in the elastic modulus of the after the crystals separated. The crystals were filtered, structure due to alteration of the electric charge of washed with the appropriate acid and then dried over acid and potassium hydroxide. The results obthe structural unit, considered to be a polypeptide sulfuric tained are summarized in the table. chain rich in hydroxy amino acid residues; (b) TABLEI charging of the structural unit through phosphorylN-HALOMETHY LPHTHALIMIDES ation of the hydroxyl groups by ATP, are to a large Yield extent independent of assumed structural details. Comcrude, 7-M. p.. '(2.-
7
(7) J. Needham, Shih-Chang Shen, D. Needham and A. S. C. Lawrence, Natura, 147, 766 (1941).
INSTITUTE FOR HIGHPOLYMER RESEARCH BROOKLYN POLYTECHNIC INSTITUTE RECEIVED APRIL3, 1948 BROOKLYN, NEWYORK GATESAND CRELLINLABORATORIES OF CHEMISTRY CALIFORNIA INSTITUTE OF TECHNOLOGY PASADENA, CALIFORNIA
Purification of N-Hydroxymethylphthalimide through a Molecular Compound with Pyridine BY EUCLID J. SAKELLARIOS
In connection with the synthesis of N-alkylated phthalimides, we have prepared N-hydroxy-
pound
%
Crystn. solvent
Obs.
Prev.5
Ethyl acetate 136.5 132-1334 Chloro- 93 Bromo- 91.1 Ethyl acetate 151.5 149-1W 92.3 Benzene-ethyl acet. 155.5 153' Iodo5 Best previously reported. RESEARCH LABORATORY THEPIRAEUSDYEWORKS (FORMERLY s. A. OECONOMIDES AND CO.) NEWPHALERON, NEAR PIRAEUS RECEIVED FEBRUARY 24, 1948 ATHENS. GREECE (1) Sachs, Bey., 81, 1231 (1898). (2) Sacha, ibid., 81, 3230 (1898). (3) Buc, THISJ O U R N A L , 69, 254 (1947). (4) Gabriel, Bcr., 41, 242 (1908). ( 5 ) Gabriel, Ber., 81, 1229 (1898).
