a convenient method for reduction of lmines using zinc powder .pdf

7/28/2019 A Convenient Method for Reduction of lmines Using Zinc Powder .pdf

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P e r g a m o n Tetrahedron Letters 39 (1998) 8873-8876T E T R A H E D R O N

L E T T E R S

Org anic React ion in Water . Part 1 . A C onvenient M ethod fo r Reduct ion ofl m i n es U s i n g Z i n c P o w d e r

Takeh i to Ts u kl n ok i * , Y os h i h aru M i toma , Sa toko N agas h i ma , Takatos h i K aw aj f ,I wao Has h l moto* an d M as as h i Tas h i ro

Tohwa Institute for Science,Tohw a University,1-1-1, Chikushigaoka, Minam i-ku, Fukuoka 815, Japan

~Depamnent of IndustrialChemistry, WskayamaNationalCollege of Technology,Nojim a 77, Nata-machi,Goboh, Wakayama644, Japan

Rec eived 25 August 1998; revised 5 September 1998; accepted 11 September 1998Ab strac t: Reduction fimineswas performedwith zincpowder n 5% aqN aOH solution withoutan yorganic solvents undea"mild conditions,and the eor~spon dingamines were obtained n good yields. 1998 Elsevier Science Ltd. All rights reserved.T h e r e d u c t i o n o f i m i n e s le a d i n g t o a m i n e s i s e f f ec t e d b y v a r i o u s m e t h o d s . ] F o r e x a m p l e , m e t a l h y d r i d e s

su c h a s L iA IH 4 ,2 NaB H4, 2 Bu2SnCII-I, 3 ( r I -C~Hs)2MoH2, 4 and RuI-ICI(PPh3)3 , s h ydr oge na t io n ca ta lysts6 l i k eP d - C a n d P t , a n d l a n t h a no i d s s u c h a s Y b7 a re u su a l l y e m p lo y e d a s m e ta l li c r e a g e n t s i n a n o rg a n i c so lv e n t fo rp r e v e n t in g p o s s i b l e h y d r o l y s i s o f i m in e s . H o w e v e r , m e t h o d s u s i n g m e t a l h y d r id e s a n d l a n t h a n o id s w h i c h h a v ea m o i s tu re - se n s i t i v e c h a ra c t e r sh o u ld b e c a r r i e d o u t in a d r i e d o rg a n i c so lv e n t a n d /o r a n i n e r t g a s , a n d i n t h e c a seo f h y d ro g e n a t io n , t h e r e a c t i o n sh o u ld b e u n d e r t a k e n w i th an e x p e n s iv e c a t a ly s t i n a n a n h y d ro u s o rg a n i c so lv e n tu n d e r h ig h p re ssu re . Th e re fo re , t h e se m e th o d s e n t a i l t e d io u s p ro c e d u re s . Fu r th e rm o re , r e c e n t ly , in c o n n e c t io nw i th e n v i ro n m e n ta l c o n c e rn s , t h e re i s g ro w in g in t e re s t i n sy n th e t i c o rg a n i c r e a c t i o n s i n w a te r w i t h o u t a n yo r g a n i c s o l v e n t s w h ic h a re e n v i ro n m e n ta l l y - f r i e n d ly , W a te r h a s m a n y a d v a n ta g e s a s a so lv e n t fo r o rg a n i cre a c t i o n s f ro m th e a sp e c t s o f c o s t , sa fe ty , s im p le o p e ra t i o n a n d e n v i ro n m e n ta l c o n c e rn s a s c o m p a re d w i th u se o fa n o rg a n i c so lv e n t , a n d m a n y o rg a n i c r e a c t io n s su c h a s t h e D ie l s -A ld e r r e a c t io n , p in a c o l c o u p l in g , t h e a ld o lr e a c t i o n a n d so o n h a v e b e e n r e p o r te d .S W e h a v e b e e n c o n t in u o u s ly i n v e s t ig a t i n g r e d u c t iv e d e h a lo g e n a t io n o fh a l o g e n a te d c o m p o u n d s a n d r e d u c t iv e c o u p l in g r e a c ti o n o f c a r b o n y l c o m p o u n d s w i t h m e t a l s i n a q u e o u s m e d i a. 9W e r e p o r t h e r e o u r s i g n i f i ca n t f i n d i n g th a t i n 5 % a q N a O H s o l u t io n w i t h o u t a n y o r g a n ic s o l v e n t s , z i n c p o w d e ri s e f f e c t i v e fo r t h e r e d u c t io n o f im in e s t o g iv e t h e c o r re sp o n d in g a m in e s u n d e r m i ld c o n d i t i o n s w i th a s im p lep r o c e d u r e .

W h e n i m i n e s l a - q w e r e t r e at e d w i t h z in c p o w d e r i n 5 % a q N a O H s o l u t io n a t r o o m t e m p er a tu r e ,r e d u c ti o n p r o c e e d e d a n d t h e c o r r e s p o n d i n g a m i n es 2 a - q w e r e o b t a i n e d i n 5 3 - 8 8 % y i e l d s ( T a b l e 1 ). F u r t h e r,w e h a v e f o u n d t h a t n o t r ac e s o f a m i n e s a n d c a r b o n y l c o m p o u n d s f o r m e d b y h y d r o l y s i s o f i m in e s w e r e o b t a in e di n o u r m e t h o d t h o u g h i m i n e s t e n d t o b e h y d r o l y z e d i n a c i d ic o r b a s i c s o l u t io n , l I n c o m p a r i s o n w i t h o t h e r c o n -

0040-4039/98/$ - see front m atter 1998 Elsevier Science Ltd. A ll rights reserved.PII: S0040-4039(98)01904-2


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9 1 _ _N _ R 3 Z n R ~ C I.t_ N _ R 1 1R 5 % a q . N a O H S o lu tio n R 2 " H + R ~ - - ~ - R zr o o m te m p . ~ H ~ H1 2 3S c h e m e 1

ven t iona l methods , som e advan tages o f ou r m ethod a r e the f ac t that , s ince the react ion can be don e in wate r a troo m temperature und er atm ospher ic pressure, i t is safe, and that hyd roge n gas is not neces sary because thep ro ton sou rce i s wa te r ; f u rthermore , Z n powde r i s cheap compared wi th metal hyd r ides , hyd rogena t ion ca ta ly s tand lan thanoids , a nzl is not sensi t ive to oxy gen and water, so i ts handling is very easy . In the cas e of ald imineslb-e having a subst i tuent group on an aromatic r ing , react ion t ime is shor tened, but the reason for the ef fect ofthe subs t ituen t g roup i s no t c lea r now. As the subs ti tuent R 3 was more bu lky ( l f -g and 1 h - j ) , i t took longert ime to comple te the r e ~ o n because the s te r ic h ind rance o f subs t i toen t R 3 poss ib ly p reven ts ad so rp t ion o f thecarbon -n i t rogen doub le bond on the su r f ace o f z inc powder . The r educ tion o f a ld imines lk - ! hav ing aheterocyc le wa s also performed. Our m ethod is not l imited to ald imines and work s as w ell with al iphatic im ineand kefimines. How ever , in the case o f N-d ipheny lmethy lenean i line ( lp ) , conver s ion o f lp in to amine 2p wason ly 50%, even though b y the tr ea tmen t o f l p under same cond i t ions fo r 120 h. I n addi tion , even though thereaction w as carr ied out at 60 'C und er u l trasonication , the formation o f 2p wa s not increased, but the reactiontime wa s shor tene d (120 - ,8h ) . In terest ingly, by adding NH 4C1 to the reaction system , the reduction of l psmoo th ly p roceeded to a ffo rd 2p in 74% iso la ted y ie ld. On the o ther hand , in the case o f ox im e l q , s imi la rly,amine 2q (R 3=H) w h ich wou ld r esu l t f rom over reduc t ion was ob ta ined in 63% y ie ld w i th no t race o fhyd roxy lamine . A smal l &-noun t o f d iamines 3a- e w as fo rmed as a by -p roduc t . I n the case o f imines l f -g andl i - j , th e fo rmat ion o f d iamine tended to be increased . The fo rmat ion o f d iamines in an aqueous so lu tion i spar ticu lar ly in terest ing , s ince usually d imef izat ion of aldimines pro ceeds und er anh ydrou s condit ions . ~In a very d i lu ted aqueous alkaline so lu t ion , 1% aq NaO H, reduction of l a occu rred as well as in 5% aqNaO H, g iv ing 2a in 83% y ie ld , a l though r eac tion time i s p ro longed (7 - ,19h ) . W hen the r educ t ion o f l a in 1%aq NaO H w as carr ied out unde r u l trasonic ir radiation , the reaction w as accelerated (19 - ,1 .5 h) , bu t the molarr at io s o f p roduc t 2 a and 3 a were l it tl e a ff ec ted.

In a typical procedure, to a s t i r red mixture of N-benzylideneanil ine l a (906 r ag , 5 .00 mmol) and 5% aqNaO H so lu t ion (20 ml) a t r oo m temperatu re was g radua lly added com merc ia l ly avai lab le z inc powder (5 .00 g~2 )for 10 min . Af ter the reaction m ixture wa s s t ir red fo r 7 h r at roo m temperature, the insoluble mater ials we ref il tered off and the f i lt rate wa s extracted with ethyl acetate . The extract w as wa she d w ith water , dr ied ove r(MgSO, ) and evapo ra ted in vacuo to give a residue, wh ich was d ist i lled on a Ku gelroh r apparatus (oventem per a~ re : lS 0 - 151 C ) under r educed p ressu re (1 .3 to rT), to a f fo rd N-benzy lan i l ine 2a (750 nag , 82%) andN , N ' , l ,2 - t e t ra p h e n y l e t h y le n e d i a m i n e 3 a ( 6 4 m g , 7 % ) .

In conc lu s ion , the r educ t ion o f imincs took p lace w i th the u se o f low-p r iced z inc powder in an aqueousalkaline solution without any organic solvents and no p roduc t ion o f hyd ro lyzed p roduc ts o f imines to a f fo rdthe co r r espond ing amines .

Fur the r s tudy o n extension of th is react ion a nd d imerization o f imines is under w ay .


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8 8 7 5

Ta ble 1. Redu ction and Co upl ing of Imines Using Zn Pow der in Aque ous Solutionwithout O rganic Solventsa

I so l a te d Y i e l d / * /.I m i n e s R 1 R 2 R 3 T i m e / h b 2 3

l d 0 - H- - - ~ - -C H 3 2 .2 8 3 31 O - .- - O - ~ ~.~ 8~ 4

l g ~ .- - " - O ~.~~H3 7 6 1 5I h ~ H- -CH3 0. 2 53 -I i ~ - - H - i so -p ropy l 5 .2 53 20l j 0 - - H - - - 0 5 . 2 7 1 1 5l k ~ H - - - ~ 0 . 2 6 3 3

I m CH 3((;H2)4- H- -(CH2)sCH3 31 .2 64 -I n ~ 0 - - -H 3 0 . 2 8 6 -l o 0 - - CH3- - - ~ 15.2 8 3 6lpo O - O - - 0 ~.~ ~4 -l q ~ H - -OH 22 .2 63 (R3--H ) -

aSubstmte : 5.00 mm ol, Zn : 5g (76.5 mm ol), bThe ime (10 min) of adding Zn p owd er o thereaction vessel Is included In the m entioned reaction ime. c NH4CI 1.96 g, 36.7 m mo l) was us ed.


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R e f e r e n c e s a n d N o t e s1. a) Harada, K .; Patai, S. The Chemistry of the Carbon Nitroge n Double B ond; John Wiley and Sons,

Inc. : New York, 1970 ; pp. 276-298. b) House, H . O. M od e m S y n the t i c R e ac t ions ; Benjamin: MenloPark, 19 72; pp. 209 -211. c) Huflman, J. W . Comprehensive Organic Synth esis; Pergamon Press:Oxford, 199 1; vol. 8 , pp. 123-124. d) March, J. Adv anc ed Organic Chemistry; John Wiley and Son s ,Inc.: New York, 1992; p. 918 .

2. Hutchins, R. O.; Hutchins, M. K. Comprehensive Organic Synthe sis; Pergamon Press: Ox ford, 1991;vol. 8, pp. 25-78.

3. Sh ib ata , . ; Moriuchi-Kawakami, T. ; Tanizawa, D. ; Suwa, T . ; Sugiyama, E. ; Matsuda, H. ; Baba, A. J.Org. Chem . 1998, 63 , 383-385.

4. Minato, M.; Fujiwara, Y.; Ito, T. Chem. Le t t . 199 5 , 647 -648 .5. Mizush irna, E.; Yam aguchi, M.; Yam agishi, T. Chem. Le t t . 199 7 , 237- 238 .6. Freifelder, M. Catalytic Hydrogenation in Organic Synthesis Procedures a nd Comm entary; John

Wiley and Sons, Inc. : New York, 1978; pp. 65-77.7. Takaki, K.; Tsubak i, Y.; Tanaka, S.; Beppu, F.; Fujiwara, Y. C he m . L e t t . 199 0 , 203 -204 .8. a) Li, C.-H . ; Chan, T.-H . Organic Reac t ions in Aqueo us M ed ia; John Wiley and Sons, Inc. : New

York, 1997 ; pp. 13-18 9. b) Lubineau, A. ; Au gt, J . ; Queneau, Y. ; Synthes is 19 94 , 741-760. c ) Li , C . -J . , Chem . Rev . 1993, 93 , 2023-2035.

9. Fo r example, see: a)Tas hiro, M.; Nakayama, K. J. Chem. Soc., Perki n Trans. 1 . 1983, 2315-2318. b)Tashiro, M.; Mataka, S. ; Nakamu ra, H . ; Nakayama, K. J . Chem . Soc . , Perk in Trans . 1 . 1 9 8 8 , 1 7 9 -181. c) Tsuzuki, H . ; Iyama, H. ; M ashimo, T. ; Mukumoto, M .; Tsukinoki, T. ; Mataka, S. ; Tashiro, IVtChem. Express 1993, 8, 495-498. d) Tsukinoki, T. ; Kakinami, T. ; I ida, Y. ; Ueno, M.;Ueno, Y. ;Mashimo, T . ; Tsuzuki, H . ; Tashiro, M. J. Chem. Soc . , Chem. Commun. 1995, 209-210. e) Tsukinoki,T .; Kaw aji, T; Has him ot, I .; l~Aatak~a, S. ; Tas hiro, ~ C he m . L e t t . 19 97 , 235-236. f) Tsukinoki, T. ;Kawaji , T. ; Hashimoto, I . ;E toh , T. ; Sahade, D. A. ; Tashiro, IVL Eng. Sci. Rep. K yus hu Univ. 19 97 ,19, 15-18. g) Sahade, D. A.; Mataka, S.; Sawada, T.; Tsukinoki, T.; Tashiro, M. Tetrahedron Lett .1997, 38 , 3745-3746.

10. a) Bruylants, A.; Med icis, E. F.; Patai, S. The C hemistry of the Carbon Nitrogen Dou ble Bond; JohnWiley and Sons, Inc. : New York, 1970; pp. 465-501. b) March, J. Adva nced O gan ic Chemis try ; JohnWiley andSons,Inc. : New York, 1992; pp. 884-885.

11. Robertson, G. M. Comprehensive Organic Synthe sis; Pergamon Press: O xford, 1991; vol. 3,pp. 579-582.12. When we investigated the minimum amount of Zn pow der which is necessary for the reduction of la ,we found that the reduction took place with 654 mg of Zn powder which is twice molar of substrateunder the same reaction conditions. But w ith equimolar Zn p ow der for l a , the start ing material remained.Ho we ver, other substrates besides l a needed 5 g of Zn po wd er for reduction.

a convenient method for reduction of lmines using zinc powder .pdf

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