15 Biological Chemistry Part (ii) Nucleic Acids (a) Nucleosides and Nucleotides By G. SHAW School of Chemistry University of Bradford Bradford BD7 1DP 1 Nucleoside Antibiotics and Constituents of tRNA 1-Methylisoguanosine (1)(doridosine) has been isolated from the marine sponges Tedunia digitutu ’,* or Anisodoris nobilis3 by different workers and reported to have powerful muscle-relaxant and cardiovascular activity when administered orally in mammals; since it is resistant to adenosine deaminase it is thought to act as a long-acting adenosine. It has been synthesized* from the imidazole nucleoside (2) (Scheme 1)or by methylation of isoguanosine with methyl iodide and potassium AcO OAc AcO OAc (2) IH (Rf= P-D-ribofuranosyl) Rfs (1) Reagents i MeNCO; ii NH, H,O Scheme 1 A novel and reportedly highly efficient synthesis of showdomycin (3) from the cyclobutene derivative (4)has been recorded5 (Scheme 2) and an interesting cine-substitution reaction in a 1,4-dinitropyrazole nucleoside (5) has led6*’ to a new J.Bairdlambert J. F. Marwood L. P. Davies and K. M. Taylor Life Sci. 1980 26 1069. R. J. Quinn R. P.Gregson A. F. Cook and R. T. Bartlett TetrahedronLett. 1980 21 567. F. A. Fuhrman G. J. Fuhrman Y. H. Kim L. A. Pavelka and H. J. Moshe Science 1980,207 193. A. F. Cook and R. T. Bartlett J. Org. Chem. 1980,45 4020. T. Inoue and I. Kuwajima J. Chem. SOC.,Chem. Commun. 1980,251. J. G. Buchanan A. Stobie and R. H. Wightman Can.J. Chem. 1980,58 2624. ’J. G. Buchanan A. R. Edgar R. J. Hutchinson A.Stobie and R. H. Wightman J. Chem. Soc. Chem. Commun. 1980,237. 299 300 G. Shaw uoSiMe3 -& phCOO,o~ OSiMe NOH OSiMe (4) rl PhCOO OCOPh PhCOO 7PhCOO OCOPh 0 Reagents i 2,3,5-tri-O-benzoyl RB-1-acetate SnCI,; ii LiN(SiMe,), Me,SiCI NOCI; iii at room temperature for 2 days; iv NH,,MeOH (CF,CO),O Scheme 2 AcO AcO OAc AcO OAc (5) ii 1 6AcO (6) AcO OAc (7) Reagents; i KCN; ii HJPd; iii NH,CH=&H AcO- NaOMe MeOH Scheme 3 route to formycin (6) (Scheme 3). A new synthesis of pyrazofurin (pyrazo- mycin) (8) from the aminopyrazole nucleoside (7)via photolytic replacement of a diazonium group with hydroxyl has been reported.8 D-Ribose and L-glutamate have been found’ to be the principle precursors in the biosynthesis of both pyrazofurin and formycin.(8) J. G. Buchanan A. Stobie and R. H. Wightman J. Chem. SOC.,Chem. Comrnun. 1980,916. ’J. G. Buchanan M. R. Hamblin G. R. sod and R.H. Wightman J. Chem. SOC.,Chem. Commun. 1980.917. Biological Chemistry -Part (ii)a Nucleosides & Nucleotides 301 5-(Methylaminomethyl)-2-thiouridine(9) a rare nucleoside of tRNA has been synthesized" (Scheme 4)and a new route" to wyosine (10) involves the amino- imidazole nucleoside (11)(Scheme 5). 0 H 1ii SN Rf (9) AcO OAc Reagents i HCO,Et NaH NH,CSNH,; ii CF3C02H HN(SiMe,), 1,2,3,5-ribofuranosyl tetra-acetate SnCI,; iii NH, MeOH Scheme 4 0 (11) (10) Reagents i CNBr BrCH,COMe Scheme 5 9-p-D-Ribopyranosylhypoxanthine(12) has been isolated" from Streptornyces antibioticus and synthesized by conventional means.The pyrazole structure assigned to polyoxin N and described in the previous Report has been revised13 to the imidazolone (13),similar to nikkomycin B (14) which was obtained from the culture filtrate of S. tendae. The structure of the latter was confirmed by synthesis of a diastereoisomeric mixture of the attached amino-acid (15). 0 (N' p N /IH N RBp (12) (R = 0-D-ribopyranosyl) H. Vorbruggen and K. Krolikiewicz Liebigs Ann. Chem. 1980 1438. T. Itaya T. Watanabe and H. Matsumoto J. Chem. SOC.,Chem. Commun. 1980 1158. l2 D. L. Kern P. D. Cook and J. C. French J. Heterocycl. Chem. 1980 17,461. 13 M. Uramoto K. Kobinata K.Isono T. Higashijima T. Miyazawa E. E. Jenkins and J. A. McCloskey Tetrahedron Lett. 1980,21 3395. l4 W. A. Konig W. Hass W. Dehler H. P. Fiedler and H. Zahner Liebigs Ann. Chem. 1980 622. 302 G. Shaw C O NCO,H H T HO I I HCMe H,NCH IHOCH HO OH CH-CH-CH-CO,HI I OH NH OH 0 @* 0 HO OH OH OH A new cytokinin (16) containing a o-hydroxybenzyl group has been isolated" from Zantedeschia aethiopica (cuckoo-pint) ; 2-deoxyuridine and thymidine have been extracted16 from the starfish Acanthasterplanci and the C-nucleoside agropine (17) has been isolated from crown gall tumours.17 Adenomycin has been assigned'* the structure (18) and X-ray crystallography of furanomycin which can be regarded as a C-nucleoside shows it to have the structure (19).l9 Neplanocin A a carbocyclic nucleoside analogue with anti-tumour activity obtained from Ampullariella regularis has the structure (20).20 HOCH,m o w -b A d e OCOCH(NH,)CH,OH HO OH HO OH (18) HO OH 15 H.J. Chaves das Neves and M. S. S. Pais Tetrahedron Lett. 1980 21 4387. 16 T.Komori Y. Sanechika Y. Ito J. Matsuo T. Nohara and T. Kawasaki Liebigs Ann. Chem. 1980 653. 17 D. T.Coxon A. M. C. Davies G. R. Fenwick R. Self J. L. Firmin D. Lipkin and N. F. James Tetrahedron Lett. 1980 21,495. 18 T.Ogita N. Otake Y. Miyazaki and H. Yonehara Tetrahedron Lett. 1980,21 3203. 19 M. Shiro H.Nakai K.Tori J. Nishikawa Y. Yoshimura and K. Katagiri J. Chem. SOC., Chem. Commun. 1980,375. 20 M. Hayashi S.Yaginuma N.Muto and M. Tsujino Proc. 8th Symp. Nucleic Acids 1980,IRL Press London New York. Biological Chemistry -Part (ii)a Nucleosides & Nucleotides 2 Nucleosides Reviews have appeared describing the new bicyclic ketone route to C-nucleosides2' and the photochemistry of purine nucleosides.22 The former method has been applied23 to the synthesis of 2-methylated C-nucleosides and a 9-deazapurine nucleoside namely the inosine analogue (21) has now been synthesized from ribo~ylacetonitrile~~ (Scheme 6). Ph,CO CH2CN + 00 X Reagents i (Me,N),CHOBu'; ii CF,CO,H H20 CHCl,; iii MeSO,CI Et,N CHCl,; iv PhCH,NHCH,CO,Et DMF; v NaOEt; vi Me,NCH(Oneopentyl),; vii NH, MeOH; viii sodium naphthylide THF at 20 OC for 18 h Scheme 6 Other novel C-nucleosides which have been described2' include the C-nucleoside isomer (22) of bredinin the indole derivative (23) which was prepared by dehydra- tion of a 2-(pentahydro~ypentyI)indolone,~~ and the purine analogue (24)27 (Scheme 7).Ribofuranosyl-pyrazoles,including (25) have been prepared from the ribofuranosyl-ethyne (26) and hydrazine28 and from al10se.~' N OH H O M Rf<-)CONH,N HO N H (22) (23) " R. Noyori and T. Sato Kaguku No Ryoiki Zokan 1980 169. '' M. Rufalska and G. Wenska Wiad. Chem. 1980 34.9. 23 T. Sato H. Kobayashi and R. Noyori Tetrahedron Lett. 1980,21 1971. 24 M. I. Lim R. S.Klein and J. J. Fox Tetrahedron Left. 1980 21 1013. 25 M. S.Pwnian and E. F. Nowoswiat. J. Org. Chem. 1980,45,203. 26 F. G. Gonzalez Carbohydr.Res. 1980,80 37. 2' C. K. Chu K. A. Watanabe and J. J. Fox J. Heterocycl. Chem. 1980,17 1435. 28 J. G. Buchanan A. R. Edgar R. J. Hutchinson A. Stobie and R. H. Wightman J. Chem. SOC. Perkin Trans. 1,1980 2567. 29 J. G. Buchanan M.E. Chacon-Fuertes A Stobie and R. H. Wightman J. Chem. SOC. Perkin Trans. 1 1980 2561. 304 G. Shaw CHO PI,COyycN +i JJNNHCONH2CN ii 4 00X Reagents i NH,NHCONH,; ii NaOEt; iii CH(OEt), HC1 Bu”0H Scheme 7 An interesting new route3’ to arabinofuranosyladenine (27) involves cyclization of 8-carbamoyl-2’-O-tosyladenosine(28). In pyridine-water the amide group acts as an 0-nucleophile to form the cyclic nucleoside (29);after hydrolysis and decarboxylation this produces (27). In contrast in the more alkaline N ‘N ‘N 3N’-tetramethyl-guanidine solution the amide is a N-nucleophile and the stable derivative (30)is the sole product (Scheme 8).Full details3’ of the synthesis of arabinofuranosyladenine(27) and of hypoxan-thine (31)by cyclization of the appropriate aminoimidazole arabinosides (32)and Ho (30) Reagents i pyridine water; ii N1N1N3N3-tetramethylguanidine Scheme 8 30 K. J. Divakar and C. B. Reese J. Chem. SOC.,Chem. Commun. 1980,1191. K. Kadir G. Mackenzie and G. Shaw J. Chem. SOC.,Perkin Trans. I 1980,2304. Biological Chemistry -Part (ii)a Nucleosides & Nucleotides 0 I HO I (32) X = CN *’ (31) (33) X = CONHz (33) respectively with formamidine or with triethyl orthoformate and ammonia have been published.The hitherto unknown 3-methyl-2’-deoxyadenosine(34) has been prepared32 by methylation of the (formy1amino)imidazole deoxyriboside (35) followed by reduc- tion to the formamidine (36),which cyclizes. The adenosine (34) is!abile at pHs7.0 when it produces 3-methyladenine (37) whereas at pH 8.98 the N-(formy1)- aminoimidazole nucleoside (36) is obtained. C(NH,)=NOCH,Ph C(NH,)=NH NMeCHO (34) R = dRf dR$ (35) dRC (36) i37j R = H -(dRf = 2‘-deoxy-P -D-ribofuranosyl) An improved synthesis33 of 2,3,5-tri-O-benzoylribofuranosyl azide in 98% yield from the l-O-acetate and trimethylsilyl azide has been described. The azide has been used in one3 of two syntheses3’ of 8-aza-3-deazaguanosine (38). 3’-Alkyl-uridines have been prepared36 in conventional manner from the ribose derivative (39) which was obtained from the keto-sugar (40) with either a Grignard reagent or an alkyl-lithium followed by deblocking and treatment with periodate and borohydride.A useful route to 5’-deoxy-5’-azido-nucleosides, including 5‘-deoxy-5’-azidothymidine in one step from thymidine and Ph3P CBr, and LiN3 in 90% yield has been described.37 5’-Deoxy-5‘-iodoadenosine has been shown3* to cyclize with zinc in pyridine to a 7,8-dihydro-5’,8-cyclo-5’-deoxyadenosine (41) with an R configuration at C-8. ’’ T. Fujii T. Saito and T. Nakasaka J. Chem. SOC.,Chem. Commun. 1980,758. 33 W. Schorkhuber and E. Zbiral Liebigs Ann. Chem.. 1980 1455. 34 R. A.Earl and L. B. Townsend. Can. J. Chem. 1980,58.2550. 35 R. B. Meyer G.R. Revankar P. D. Cook K. W. Ehler M. P. Schweizer and R. K. Robins J. Heterocycl. Chem. 1980.17 159. 36 A. Rosenthal and S. N. Mikhailov. Carbohydr. Res. 1980,79,235. 37 I. Yamamoto M. Sekine and T. Hata J. Chem. SOC.,Perkin Trans. 1 1980,306. 38 J. Zylber R. Pontikis A. Merrien C. Merrienne M. Baran-Marszak and A. Gaudemer Tetrahedron 1980.361579. 306 G. Shaw The novel synthesis of an analogue of NAD that was described in the previous Report has been extended3’ to include the preparation of the ribosylpyridinium salt (42) from 2,3-0-isopropylideneribofuranosylamineand a 1-(2,4-dinitro-phenyl)-3-benzoylpyridiniumsalt and further examples of the use of tetraisopropyl- disiloxane as a protecting group with cytosine arabinoside and 1-(6-deoxy-a-~-talofuranosy1)uracil have been de~cribed.~’ Other novel 0-protecting groups include the pyridine N-oxide group (43) which may be removed under mild and the use of zinc bromide to remove methoxytrityl groups in nucleoside and nucleotide chemistry has been reviewed.42 Trimethylsilyl iodide has been used for the first time43 in nucleoside synthesis to prepare 2,3,5-tri-O-benzoylribosyl iodide from the acetate and it may be condensed with a silylated base in situ to give nucleosides.The use of hydroxylamine acetate for the regioselective 2’-0-deacylation of purine and pyrimidine ribonucle~sides~~ and of pentafluorophenyl benzoate4’ for the rapid acylation of 2‘-deoxycytidine in 90% yield at room temperature during a day have been recommended Further examples of the use of fluorine in acetic acid for the fluorination of nucleosides have been given.46 S-P-Rf (45) Me,N 1 0 mN-0 CHN~ (43) (44) 39 Ch.R. Winne J. A. Lepoivre and F. C. Alderweireldt Bull. Soc. Chim. Belg. 1980,89,67. 40 W. T. Markiewicz N. S. Padyukova Z. Samek and J. Smrt,Collect. Czech. Chem. Commun. 1980 45,1860. 41 Y. Mizuno T. Endo A. Takahashi and A. Inaki Chem. Pharm. Bull. 1980,28,3041. 42 V.Kohli H. Blocker and H. Kosler Tetrahedron Lett. 1980,21,2683. 43 Z.Tocik R. A. Earl and J. Beranek Nucleic Acids Res. 1980,8,4755. 44 Y.Ishido N. Sakairi K. Okazaki and N. Nakazaki J. Chem. Soc. Perkin Trans. 1 1980 563. 45 J. Igolen and C. Morin J. Org. Chem. 1980,45,4802. 46 B.Schwarz. D. Cech A. Holy and J.Skoda Collect. Czech. Chem. Commun. 1980,45,3217. Biological Chemistry -Part (ii)a Nucleosides & Nucleotides 307 Alkylation of nucleosides continues to excite attention. Guanosine has been shown4’ to produce the C-8-substituted derivative (44) by treatment with benz[a]anthracene 5,6-oxide at pH 9.5 over 4 days at 37°C and to ben~ylate~~ with the carcinogen N-nitroso-N-benzylurea mainly on 0-6 and N-2. An examination of the methylation of various nucleosides in the presence of t-butyl peracetate has that C-methylation occurs at pH 1-4 but that at pH4-10 there is increasing N-methylation in all the common pyrimidine and purine nucleosides. Permethylation of adenosine and guanosine has been a~hieved,~’ using trimethylaniliniwn methoxide but inosine and xanthosine are cleaved by the reagent to produce methyl aglycones.Further applications5’ of the sulphur-extrusion method to nucleosides have been outlined including the conversion of 4-thiouridine into various 4-(substituted a1kyl)pyrimidine nucleosides uia 4-alkylthio-derivatives using triphenylphosphine and a strong base and further details of the replacement of the 6-amino-group of an acylated adenosine in an appropriate anhydrous medium by photolysis in the presence of pentyl nitrite have appeared.” N.m.r. relaxation studies of 13C-labelled uracil in tRNA have been reported53 and an n.m.r. study of 5-substituted uridines has that the substituent affects the N-1-C-1’ and the C-1’-0-1’ bonds in opposite ways. Ultrasonic relaxation studies have shownss that the syn-anti glycosyl conformational barrier is reduced when 2’-deoxyadenosine is bound to ethidium bromide and this is considered to be a relevant model for intercalation studies.3 Nucleotides Phosphoryl tris-triaz~le’~ have been proposed as and tri( 1-imidaz~lyl)phosphine~~ phosphorylating agents that are especially useful for the preparation of nucleoside 3‘-phosphotriesters the latter after oxidation wit) iodine water. g-Chlorophenyl phosphorodichloridate followed by oxidation of intermediate phosphite esters with iodine has also been used58 to prepare mononucleotides and a similar system has been applied” to the formation of inter-nucleotide bonds. Side-reactions in nucleo- tide synthesis using phosphorochloridates are reported to be diminished by using molecular sieves as acid scavengers,6o 06-phosphorylation or -thiophosphorylation of guanosine derivatives is aided6’ by the use of 4-(dimethy1amino)pyridine as a catalyst and selective 5’-0-phosphorylation especially of oligonucleotides has 47 K.Nakanishi H. Komura I. Miura and H. Kasai J. Chem. Soc. Chem. Commun. 1980,82. 48 R. C.Moschel W. R. Hudgins and A. Dipple J. Org. Chem. 1980,45,533. 49 M. F.Zady and J. L. Wong J. Org. Chem. 1980,451,2375. ’O G. R. Pettit R. M. Blazer J. A. Einck and K. Yamauchi J. Org. Chem. 1980,45,4073. ” A.Yamane H. Inoue. and T. Ueda Chem. Pharm. Bull. 1980,28,157. ” V.Nair and S. G. Richardson J. Org. Chem. 1980,45,3969. ” W. D. Harnill Jr. W. J. Horton and D. M. Grant J. Am. Chem. SOC.,1980,102,5454.s4 E.Egert H. J. Lindner W. Hillen and M. C. Bohrn J. Am. Chem. SOC.,1980,102,3707. ” F.Jordan S. Nishikawa and P. Hernrnes J. Am. Chem. SOC.,1980,102,3913. ” A.Kraszewski and J. Stawinski Tetrahedron Lett. 1980 21 2935. 57 T.Shimidzu K. Yarnana A. Murakarni and K. Nakamichi Tetrahedron Lett. 1980,21,2717. ’’ D. Molko R. B. Derbyshire A. Guy A. Roget and R. Teoule Tetrahedron Lett. 1980 21 2159. s9 K.E.Ogilvie and M. J. Nerner Tetrahedron Lett. 1980,21,4145. 6o V.Kohli H. Blacker and H. Koster Tetrahedron Lett. 1980.21 501. ” H. P.Daskalov M. Sekine and T. Hata Tetrahedron Lett. 1980.21 3899. 308 G. Shaw been achieved6* using 5 -chloro-8-quinolyl phosphate in the presence of (PySe) and Ph3P at room temperature over twelve hours in 92% yield.The methyl group has been found to be as a protecting group for phbsphate esters in nucleotide synthesis and it may be removed by t-butylamine at 46 "Cover fifteen hours. Interest in cyclic phosphates continues. The enzymatic synthesis and configur- ational analysis of the (R,)and (Sp)diastereoisomers of [a-"0]-2'-dADP from (Sp)and (Rp) diastereoisomers of cC1'0]-2'-dAMP using an adenylate cyclase from Breuibacterium Ziquefaciens has been achieved.64 c[ '*0]-2'-dAMP has also been ~ynthesized~~ from the P-anilidates of c-2'-dAMP and C'802 with retention of configuration and a stereospecific synthesis of cAdo-3',5'-(Sp)-[180]mono-phosphate has been Mass spectrometry has been used to identify cAMP in plant tissue Calculations of the geometrical stabilization of 3'3'-and 2',3'-cyclic nucleotides have been made and they show68 that hydrolysis of cAMP is more exothermic owing to trans ring fusion (4-5 kcalmol-' of strain energy) and unfavourable 0-C-C-0 interactions that are relieved after cleavage of the phosphate ring.A quantum-chemical study6' has examined the effect of hydration and of pucker- ing of the ribose ring on the enthalpy of hydration of CAMP; the bridge between 0-1' and 0-5' is an important hydration site for 1 molecule of water. Syntheses and configurational assignments of diastereoisomers of the 4-nitrophenyl esters of thymidine 3'-and 5'-N-phenylphosphoramidateshave been reported," and the absolute configuration at the phosphorus atom has been determined. A novel reaction of ribose 5-phosphate and barbituric acid gives amongst other compounds the nucleotide (43 which is an inhibitor of orotidine 5'-phosphate decarboxylase." The transport of nucleotides through chloroform using diammonium diazabicyclo-octane as a carrier has been rep~rted.~' Raman perturbation difference spectroscopy has been applied73 to a study of heavy-metal-nucleotide interaction and a new fluorescent labelling agent for nu~leofides~~ is the isoquinoline (46) which alkylates UMP at the phosphate ester group to give a highly fluorescent material with an excitation maximum at 353 nm and an emission maximum at 523 nm.X-Ray crystal structures that have been determined include those of pseudocytidine hydr~chloride,~~ 5-hydroxymethyl-2'-5-acety1-2'-deoxy~ridine,~~ '' H.Takaku M. Kato M. Yoshida and R. Yamaguchi J. Org. Chem. 1980,45 3347. 63 D. J. H. Smith K. K. Ogilvie and M. E. Gillen Tetrahedron Lett. 1980,21 861. 64 J. A.Coderre and J. A. Gerlt J. Am. Chem. Soc. 1980 102,6594. '' J. A.Gerlt and J. A. Coderre J. Am. Chem. SOC., 1980 102,4531. '' J. Baraniak K. Lesiak M. Sochaki and W. J. Stec J. Am. Chem. Soc. 1980 102,4533. " R.P. Newton N. Gibbs C. D. Moyce J. L. Wiebers and E. G. Brown Phytochemism 1980,19,1909. " F.J. Marsh P. Weiner J. E. Douglas P. A. Kollman G. L. Kenyon and J. A. Gerlt J. Am. Chem. SOC.,1980 102 1660. 69 M. M. E. Scheffers-Sap and H. M. Buck J. Am. Chem. Sac. 1980,102,6422. 70 J. A.Gerlt S. Mehdi J. A. Coderre and W. 0.Rogers Tetrahedron Lett. 1980,21,2385.71 H.Komura K. Nakanishi B. W. Potuin H. J. Stern and R. S. Krooth J. Am. Chem. SOC., 1980 102 1208. '' I. Tabushi Y. Kobuke and J.-I. Imuti J. Am. Chem. SOC.,1980,102 1744. 73 M. R. Moller M. A. Bruck T. O'Connor F. J. Armatis Jr. E. A. Knolonski. N. Kottman and R. S. Tobias J. Am. Chem. SOC., 1980,102,4589. 74 S. Nishimura and M. Saneyoshi Chem. Pharm. Bull. 1980,28,1695. G. 1. Birnbaum K. A. Watanabe and J. J. Fox Can. J. Chem. 1980,SS 1633. '' P. J. Barr P. Chananont T. A. Hamor A. S. Jones M. K. O'Leary and R. T. Walker Tetrahedron 1980,36,1269. Biological Chemistry -Part (ii)a Nucleosides & Nucleotides 309 6-methy1-2’-deoxy~ridine,7~ de~xyuridine,~~ and 4-amino-l-[4-amino-2-oxo-1(2H)-pyrimidinyl]-l,4-dideoxy-P-D-glucopyranuronic (C-substance -the nucleoside fragment of gougerotin).G. I. Birnbaum R. Deslauriers T.-S. Lin G. T. Shiau and W. H. Prusoff,I. Am. Chem. Soc. 1980 102,4236. 78 G. I. Birnbaum F. E. Hruska and W. P. Niemczura I. Am. Chem. SOC.,1980,102,5586. 79 P.Swaminathan J. McAlister and M. Sundaralingam Acta Crystallogr. Secr. B 1980 36 878.