were found to react with formamide under ultraviolet irradiation to give the higher amides. The addition of formamide to %,P-unsaturated esters was achieved through the use of benzophenone as a sensitizer and high yields of succinic amide esters have bccn obtaincd. I t is proposed that the photoaddition of formamide to olefins is a free radical chain reaction involving carbamoyl radicals oCONH2 and that the olefin serves as a scavenger for these radicals. The formation of the carbamoyl radicals is assumed to take place through hydrogen atom abstraction from formamide by the excited carbonyl compound. The photoaddition of cyclic ethers to olefins can be achieved by dircct irradiation or through photochemical initiation with a ketonic compound, c.g. acetone or acetophenone, with considerably higher yields. %-Substituted cyclic ethers are the major products of the reaction[21. y-Butyrolactone and 2-pyrrolidone were found to add to terminal olefins under ultraviolet irradiation to give 2 4 - kylated y-butyrolactones in high yields 1.31, and mixtures of 3-alkylated and 5-alkylated 2-pyrrolidones 131, respectively. N-Acetylglycine ethyl ester has been shown to react with olefins or toluene when irradiated in the presence of acetone, to yield the derivatives of higher amino acids and phenyl- alanine, respectively. [Lecture at Marl (Germany). October 22nd, 19651 [VB 961 268 IE]

German version: Angew. Chem. 78, 21 1 (1966)

[I] D. Had and J. Rukach, J . org. Chemistry 29, 1855 (1964). [2] I). Elad and R. D. Yuussefjeh, J. org. Chemistry 29, 2031 ( I 964). [3] D. Ehd and R . I). Youssefyeh, Chem. Commun. I , 7 (1965). [4] D. EIad and J. Sinnreich, Chem. and Ind. 1965, 768.

Studies of Chemical Reactions by Pulse Radiolysis: Free Electrons and Free Radicals in Aqueous Solution

A . Hengfein, Berlin

Reactions of OH radicals and hydrated electrons that are produced by decomposition of water can be followed by pulse radiolysis (pulses of about 10-6 sec duration), the absorption of the hydrated electrons at 7200 8, immediately after the irradiation pulse being shown osciilographically as a function of time or the absorption spectra of the reaction products being measured. Hydrated electrons react with tetranitromethane in a bi- molecular process of rate constant (at 20 "C) 6 . 0 ~ 1010 1 mole-' sec-1, with formation of the anion o f mi-nitroform. From simultaneous observations of the disappearance of the absorption o f the hydrated electrons and of the appearance of the nitroform absorption, the extinction coefficient of electrons in water was found to be ~ 7 2 0 0 8 , = 1.55~104 1 mole-1 sec-1. Nitromethanc reacts with hydrated electrons, giving the anion CH3N02-. This is an example of the first reduction stage of an aliphatic nitro compound. The anion absorbs at 2700 (E = 2800 1 mole-1 cm-1) and undergoes a further reaction which is of the second order. In acidic solution the

undissociated radical acid CH3N7* is formed (pK =

4.5, A,,, -= 2500 A, cmax = 2 .0~103 1 m o W l cm-1). Two examples of reactions of this radical acid or its anion are charge transfer to tetranitromethane (k = 1.2: lo9 1 mole-1 sec--1) and reaction with oxygen. The solvated electron reacts with hydrogen sulfide in aqueous solution by a diffusion-controlled process, i.e., without activation energy, although the reaction in the gas phase has an energy barrier of 1.6 eV. The rapidity of the reaction i n solution is considered due to solvation effects. The heat of hydration of the electron is materially less than that of a

. 'OH

heavy negative ion. From the kinetic results it is concluded that values below 2.0 eV are commonest in the distribution of solvation energy of the hydrated electron, which agrees with calculations from the absorption spectrum of the hydrated clectron. The reaction of catalase with the OH radical is diffusion controlled, as shown by a comparison of the measured ratc constant of 8 . 3 ~ 1010 1 mole-1 sec-1 with that calculated from the Smoluchowski equation 111. For this purpose the radius of catalase, known from diffusion measurements, and the self-diffusion coefficient of water (which was treated as equal to the diffusion coefficient of the O H radical) were used. The reaction OH + catalase is diffusion controlled although 30 ?<; of the individual amino acids of catalase react with OH in a process that is not diffusion controlled. This result was discussed in the light of Noyes' theory121 of the probability of re-eiicounters in diffusion-controlled reactions. I t is expected that macromolecules will react with radicals of lower mole- cular wcight by a diffusion-controlled process, even when reaction of the isolated monomer, though fast, is not wholly diff~ision-controlled. [Lecture at Miilheim (Germany), November 3rd, 19651 [VB 963j269 IE]

German version: Angew. Chem. 78, 212 (1966)

[ I ] M . v . SmArchowski, Z. physik. Chem. B 42, 129 (1918). [21 R. M . Nuyes, J. chem. Physics 22, 1349 (1954).

Amidothio-, Fluoroamidothio-, and Fluorothiophosphates

H. H. FnIius, Rraunschweig (Germany)

Reaction of phosphorus sulfide trichloride with aqueous ammonia gives ammonium diamidothiophosphate NHq[POS(NH2)2] and diammonium amidothiophosphate (NH4)2[P02S(NH21]. These salts can be readily isolated in piire form. The anions are quite stable in neutral aqueous and alkaline solution, but in acidic solution the diamidothiophos- phate is rapidly hydrolysed to the nionoamidothiophosphate; an acidic solution of the latter can be kept for several days in the cold without significant hydrolysis. These compounds react extremely rapidly with hydrofluoric acid. In an excess of 20"<; HF the amido groups are re- placed by fluoride. Thc diamidothiophosphate thus gives the difluorothiophosphate [POSFzJ- with a small amount of the monofluorothiophosphate [P02SF]2-, and the monoamido- thiophosphate gives monofluorothiophosphate. The difluoro- thiophosphate is hydrolysed in acidic, HF-free solution to the monofluorothiophosphate. The diamiodthiophosphate reacts with F - ~ also in neutral solution, but not as far as in acidic solution. Only one amido group is replaced in an aqueous solution of the diamidothio- phosphate containing ammonium fluoride: the resulting anion is fluoroamidothiophosphatc, which exchanges its second amido group in hydrofluoric acid with formation of difluorothiophosphate. The two fluorothiophosphates are also formed on reaction of phosphorus sulfide trichloride with aqueous fluoride solu- tions. Products formed by reaction with ammonium fluoride and ammonia include the fluoroamidothiophosphate. The phosphorus-sulfur bond in fluorothiophosphates is much stronger than in thiophosphates or amidothiophos- phates owing to the electronegativity of the fluorine. This is shown by the resistance of the phosphorus sulfur bond to hydrolysis and by the fact that silver sulfide is formed only slowly on reaction with silver nitrate. The reason is clearly the increased strength of the d,-d, bond between phosphorus and sulfur, evidence of which is being sought by spectro- scopic methods. [Lecture at Braunschweig (Germany), November 29th, 19651

[VB 967,'275 IE] Geroian version: Angew. Chcm. 78. 272 (1966)

256 Aiigew. Client. interntit. Edif. 1 VCJI. 5 (1966) No. 2