December 21, 1899] 



NATURE 



189 



By this modification 3 : 7-dimethyl uric acid may be made to 

 yield chlorotheobromine and theobromine, or better still, 

 3-methyl uric acid, which can be obtained by the direct methyl- 

 ation of uric acid, may be converted successively into 3-methyl- 8- 

 chloroxanthine, which may be either methylated with methyl 

 iodide in presence of caustic potash to chlorotheobromine and 

 chlorocaflfeine, and then reduced, or first reduced to 3-methyl 

 xanthine and then methylated. As a rule, however, the 

 methylation of the chlorine compound is more easily effected 

 than that of the reduced product. Paraxanthine (i : 7-dimethyl- 

 xanthine) may be obtained from i : 7-dimethy luric acid in a 

 similar manner and also converted by methylation into caffeine. 

 The following scheme will make clear the various directions in 

 which the synthesis of caffeine has been accomplished : — 



Uric acid. 



\ 



-Methyluric 

 acid. 



\, 



1 heobromine. 



i:3-DimethyIuric 

 acid. 



Theophylline. 



1 :7-Dimethyluri< 

 acid. 



Paraxanthine. 



Tetramethyl- 

 uric acid. 



Heteroxanthine (7-methyl xanthine) has been obtained by the 

 action of phosphorus oxychloride on theobromine, which by the 

 elimination of one methyl group forms 7-methyl dichloropurine. 

 V>y boiling this substance with hydrochloric acid, 7-methyl 

 xanthine is formed. Xanthine cannot be prepared in so direct 

 and simple a manner as the above from uric acid, even when 

 phosphorus oxychloride alone is used, for the first product ob- 

 tained in this wayisSo.'iy- 2 : 6-dichloropurine instead of 8-chloro- 

 2 : 6-dioxypurine ; but by the action of a large excess of 

 phosphorus oxychloride uric acid may be made to part with its 

 last atom of oxygen. Trichloropurine is then produced, and 

 this compound has served for the synthesis of xanthine and 

 its more nearly related derivatives hypoxanthine, adenine and 

 guanine. 



When trichloropurine is treated with aqueous potash it yields 

 6 oxy- 2 : 8-dichloropurine. The latter compound may be 

 directly reduced with hydriodic acid to hypoxanthine, or con- 

 verted with alcoholic ammonia into chloroguanine, which on 

 reduction forms guanine. Aqueous ammonia converts trichloro- 

 purine into 6-amino- 2 : 8-dichloropurine, which yields adenine 

 on reduction. 



HN— CO 



I I 

 CIC C— NH 



1; il >CC1 

 N— C-N 



6-oxy- 2:8-dichloropurine. 



HN- 



HC 



li 



-CO 



I 

 C-NH 



^CH 



N — C— N 



Hypoxanthine. 



ilN^CCl 

 CIC C— NH 



N = C.NHj 

 I I 

 CIC C-NH 



^CCl 



N— C— N 



Trichloropurine. 



|; p^cci. 



-C— N 



2:8-dichloropuri: 



N = C.NH2 



I I 



HC C— NH 



II II \ 



N — C— N 

 Adenine. 



HN— CO 



I I 



NHyC C— NH 



N — C— N 



Chloroguanine. 



HN— CO 



i I 



NH».C C— NH 



^CH 



N— C— N 



Guanine. 



I 



With strong hydriodic acid, trichloropurine is converted into 

 iiiodopurine, which yields, on the one hand, with hydrochloric 

 icid xanthine, and with zinc dust and water purine, the mother 

 substance of the whole group of compounds. Though neutral 

 to litmus, purine forms salts, the nitrate and picrate being the 

 most characteristic of these compounds. 



NO. 1573, VOL. 61] 



CH 



UNI VERSITY A ND ED UCA TIONA L 

 INTELLIGENCE. 



Mr. Frank Teney, of the Geological Department of the 

 British Museum (Natural History), who has been trained under 

 Mr. Smith Woodward, has been appointed Assistant Curator of 

 the Norwich Museum. 



Mr. a. Kendle Short, a student of University College, 

 Bristol, was awarded the scholarship in physiology at the recent 

 final B.Sc. examination of London University. The scholarship 

 is of the value of 50/. per annum for two years. 



Dr. J. W. Gregorv has been appointed professor of geology 

 and mineralogy in the University of Melbourne, in succession 

 to Sir Frederick M'Coy, F. R.S. Dr. Gregory has been an as- 

 sistant in the geological department of the British Museum 

 (Natural History) for several years, and is a member of the council 

 of the Geological Society. He has been engaged in very success- 

 ful explorations^notably in British East Africa in 1S92-93, and^ 

 in Spitsbergen in 1896 — and has, in addition, contributed more 

 than fifty papers to scientific societies. The salary attached to 

 the post to which he has been appointed is 1000/. a year. 



The London Technical Education Committee have arranged 

 for a second conference of science teachers to be held during the 

 forthcoming Christmas vacation. Meetings will be held on 

 Wednesday, January 10, and Thursday, January 11, 1900, ia 

 the morning and afternoon of each day. On the first day the 

 meetings will be held in the conference room of the English 

 E^ducation Exhibition at the Imperial Institute, when the Rt. 

 Hon. Sir John Lubbock, F.R.S., will preside at the morning 

 meetings, and Sir Henry Roscoe, F. R.S., at the afternoon 

 gatherings. The second day's proceedings will take place at 

 the Shoreditch Technical Institute, Pitfield-street, Iloxton. 

 The following addresses will be delivered : — Wednesday 

 at II a.m., "Teaching of Botany in Schools," by Prof. 

 L. C. Miall, F. R.S., and "Object Lessons in Botany," by Miss 

 Von Wyss ; at 2 o'clock, on "Juvenile Research," by Prof. 

 H. E. Armstrong, F.R.S., this address will be illustrated with 

 lantern slides and experiments by juvenile assistants ,- on 

 Thursday at 11 a.m., on "Teaching of Natural History i» 

 Schools," by Prof. Woods Hutchinson, and on "Object 

 Lessons in Natural History," by Mr. J. W. Tutt ; at 2 o'clock, 

 " Metal Work as a Form of Manual Instruction in Schools," by 

 Prof. W. Ripper. Free admission will be granted to as many 

 teachers as the conference rooms will accommodate. Applica- 

 tions for tickets of admission should be made to Dr. Kimmins, 

 Bermondsey Settlement Lodge, S.E., or to Mr. C. E. Buck- 

 master, 16, Heathfield road, Mill Hill Park, W. 



The following gifts to science and education in the United 

 States are announced in Science : — The money, amounting ta 

 11,400,000 dollars, obtained by Mrs. Jane Stanford for her 

 285,000 shares of Southern Pacific stock, which she sold 

 recently, will at once be made available for the use of the 

 Stanford University. — Mr. James Jennings McComb, of New 

 York, one of the founders of the South-western Presbyterian 

 University at Clarksville, Tenn., has given 70,000 dollars to 

 the endowment fund, making his contributions amount in all 

 to 100,000 dollars. — Brown University has received an uncon- 

 ditional gift of 10,000 dollars from the heirs of the late Lucian 

 Sharpe.— The Rev. John Pike has left the reversion of half his 

 property to found two scholarships in Bowdoin College. — 

 Mr. Thomas Armstrong, of Plattsburg, New York State, who 



