SYNTHESIS AND SPECTROSCOPIC STUDY OF

SYNTHESIS AND SPECTROSCOPIC STUDY OF HETEROLEPTIC MONO-RING SUBSTITUTED TRI-AND TETRA-PHENYLTIN COMPOUNDS CONTAINING THE p-FORMYL OR p-ACETYL SUBSTITUENT IN ITS FREE, PROTECTED AND DERIVATISED FORMS Normawati Samsodin 1 , Ng Seik Weng 1 and V. G. Kumar Das* 2 ^ s t i t u t e of Postgraduate Studies and Research d e p a r t m e n t of Chemistry University of Malaya, 50603 Kuala Lumpur, Malaysia ABSTRACT Mono-ring substituted tetraphenyltins containing the p-formyl or p-acetyl substituent in its free, protected (ethylene acetal / ketal)) and derivatised (semicarbazone, oxime) forms have been synthesised. Treatment of the carbonyl-protected tetraphenyltin with iodine in DMF, followed by aqueous ΝΗ,ΟΗ yielded P h 2 S n ( C 6 H 4 - p - C R 0 C H 2 C H 2 0 ) 0 H (R=H,Me). The hydroxide condenses with 3-benzoylpropionic and dimethyldithiocarbamylacetic acids to form the corresponding triaryltin carboxylates. Regeneration of the carbonyl function in the hydroxide was achieved using tartaric acid in aqueous acetone, while treatment of the hydroxide with hydrochloric acid in chloroform/petroleum ether gave in the one step the chloride, Ph 2 Sn(C 6 H 4 -p-C(:0)R)CI. The compounds were characterised by elemental analysis, IR, multinuclear NMR and tin-119m Mössbauer spectroscopy. INTRODUCTION In the course of our studies on the antifungal and insecticidal properties of tin(IV) organyls, we have shown that the strategy of introducing a functionialised esteryl moiety as the anionic residue in triphenyltin(IV) systems as well as that of mono-ring substitution, as exemplified by ( 4 - C I C 6 H 4 ) S n P h 2 0 C ( 0 ) C H 2 S C ( S ) N M e 2 , can lead to products manifesting increased biological activity and/or selectivity 1-4 compared to the well known crop protectants, triphenyltin acetate and triphenyltin hydroxide .In an extension of this work we sought to prepare other mono-ring substituted derivatives, and in this report we detail the synthesis and spectroscopic properties of compounds containing the para-formylphenyl and para-acetylphenyl groups on tin. EXPERIMENTAL 2-(4-Bromophenyl)-1,3-dioxacyclopentane, b.p. 0 8 m m 142-44 °C (Lit 5 .b.p. 12mm 145-147 °C), and 2-(4-bromophenyl)-2-methyl-1,3-dioxacyclopentane, b.p. 0 5 m m 112-114° C (Lit6. b . p . o . 1 3 m b a r 95-98°C) were prepared by condensing 1,2-ethanediol with 4-bromobenzaldehyde and with 4-bromoacetophenone, respectively, in toluene. Synthesis of 4-[2-(1,3-dioxacyclopentyl)phenyl]triphenyltin To the Grignard reagent of 2-(4-bromophenyl)-1,3-dioxacyclopentane prepared in THF under a nitrogen atmosphere from equimolar amounts (0.12 mol) of magnesium and 2-(4bromophenyl)-1,3-dioxalane was added with stirring a solution of triphenyltin chloride (42.5 g,0.11 mol) in THF. The reaction mixture was refluxed for several hours and then hydrolysed at room temperature with a small quantity of aqueous ammonium chloride.The organic phase was separated and this was combined with chloroform extracts of the aqueous phase , and the whole dried over anhydrous calcium chloride and filtered. The filtrate upon concentrating using a rotary evaporator furnished the tetraorganotin compound as a yellow solid in 60% yield based on 2-(4-bromophenyl)-1,3-dioxacyclopentane. 1 H NMR (5,ppm): 4.0-4.2[4H,m, CH 2 (acetal)],5.8[1 H,s,CH (acetal)],7.4-7.7[19H,m,arom.] Synthesis of 4-formylphenyltriphenyltin A solution of 4-[2-(1,3-dioxacyclopentyl)phenyl]triphenyltin (5 g, 10 mmol) and 4toluenesulfonic acid (200 mg) in 150 mL of a 1:4 (v/v) water/THF mixture was refluxed for several hours, duplicating a literature procedure for the cleavage of the tin-phenyl bond .The reaction mixture was extracted with dichloromethane. The extract was washed with potassium bicarbonate and then concentrated to furnish the crude product. Recrystallisation from chloroform/petroleum ether gave the pure product in 60% yield. 1 H NMR (δ,ρρηη): 7.2-7.9[19H,m,arom.],10.1[1 H,s,CHO]

335

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Vol. 22, No. 5, 1999

Synthesis and Spectroscopic Study of Heteroleptic Mon-Ring Substituted Tri-and Tetra-Phenyltin Compounds Containing The p-Forml or p-Acetyl

Synthesis of 4-[2-(1,3-dioxacyclopentyl)phenyl]diphenyltin hydroxide 4-[2-(1,3-Dioxacyclopentyl)phenyl]triphenyltin (5.0 g, 10 mmol) and iodine (3.3 g, 13 mmol) were stirred in DMF (100 mL) at room temperature for 48h. Acetone (50 mL) was added to the reaction , followed by 30% aqueous ammonia (50 mL). Stirring was continued for 1 h and water (50 mL) then added. Further stirring yielded a solid compound which was collected and washed with water. Recrystallization from chloroform gave a yellow product in 50% yield. 1 H NMR (δ,ρριη): 1,8[1H,s,OH],4.1-4.3[4H,m, CH 2 (acetal)],5.8[1 H,s,CH ( a c e t a l ) ] , 7 . 3 7.9[14H,m,arom.] Synthesis of 4-[2-(1,3-dioxacyclopentyl)phenyl]diphenyltin 3-benzoylpropionate 4-[2-(1,3-Dioxacyclopentyl)phenyl]diphenyltin hydroxide (0.05 g, 0.14 mmol) and 3benzoylpropionic acid (0.02 g, 0.14 mmol) were heated in toluene and the water formed removed azeotropically. The removal of the solvent gave the 3-benzoylpropionate in 63% yield. Ή NMR (5,ppm): 4.0-4.2[4H,m, CH 2 (acetal)], 4.7-4.8 and 5.0-5.2[4H,m,CH 2 ( e s t e r y l ) ] , 5.9[1 H,s,CH (acetal)], 7.1-7.9[19H,m,arom.] Synthesis of (4-formylphenyl)diphenyltin hydroxide 4-[2-(1,3-Dioxacyclopentyl)phenyl]diphenyltin hydroxide (2.00 g, 4.55 mmol) in acetone (50 mL) was refluxed with 85% aqueous tartaric acid (50 mL) for several hours. The solution was concentrated to about 50 mL and water (50 mL) then added. The mixture was extracted with chloroform. The extract was dried over anhydrous calcium chloride and concentrated to a small volume to yield the hydroxide in 53% yield. 1 H NMR (δ,ρριη): 1.7[1H,s,OH], 7.2-7.8[14H,m,arom.],9.9[1H,s,CHO] Synthesis of (4-formylphenyl)diphenyltin chloride 4 - [ 2 - ( 1 , 3 - D i o x a c y c l o p e n t y l ) p h e n y l ] t r i p h e n y l t i n (5.00 g, 10.00 mmol) in 1/1 (v/v) chloroform-petroleum ether (100 mL) was stirred with 6M hydrochloric acid (150 mL) for several hours. The organic layer was separated, washed with bicarbonate and then concentrated to give the yellow product in 60% yield. 1 H NMR (δ,ρριη): 7.2-7.8[14H,m,arom.],10.0[1H,s,CHC>] Synthesis of (4-formylphenyl)triphenyltin semicarbazone (p-Formylphenyl)triphenyltin (0.20 g, 0.44 mmol) in ethanol (10 mL) was treated with a solution of semicarbazide hydrochloride (0.05 g, 0.45 mmol) and sodium acetate (0.04 g, 0.45 mmol) in water (10 mL). The mixture was briefly heated and then cooled. The solid that formed was collected and recrystallized from ethanol in 80% yield. 1 H NMR (δ,ρριη): 2.8[2H,s,NH 2 ], 5.3[1H,s,NH], 6.7[1H,s,CH], 7.2-7.8[19H,m,arom.] Other organotin compounds were prepared in a similar manner. The analytical data and melting points are listed in Table 1. Physical measurements Melting points were determined in open capillaries and are uncorrected. Elemental analyses ( T a b l e l ) were carried out by the Microanalytical Service, University College, London. The infrared spectra on the compounds were recorded as nujol mulls between NaCI or KBr w i n d o w s using a Perkin-Elmer 1300 s p e c t r o m e t e r and c a l i b r a t e d with polystyrene.Table 2a lists the IR data for selected tetraorganotins and for the triorganotin chlorides and hydroxides, while Table 2b (vide infra) gives the data for the triorganotin carboxylates. The t i n - 1 1 9 m Mossbauer data (Tables 3a & 3b) were measured at 80 Κ using a Cryophysics constant acceleration spectrometer with a 512 channel data store and 15 mCi Ca 11 S n 0 3 source at room temperature. The velocity range was calibrated with C a S n 0 3 and the spectra were fitted with a Lorentzian curve-fitting program supplied by the manufacturer. The proton, carbon-13 and tin-119 NMR spectra were recorded in CDCI 3 on a JEOL JNM GX270 spectrometer, operating at 270.1 MHz, 67.8 MHz and 100.6 MHz, respectively. A complete proton decoupling irradiation mode was used to record the 1 C spectra with the C D C I 3 functioning as internal lock. The 119 Sn spectra (Table 4) were obtained under Nuclear Overhauser suppressed conditions. All spectra were recorded at room temperature using concentrated solutions for 13C and specific concentrations for 11 Sn. The 1 C chemical shifts (relative to Me 4 Si) are accurate to ± 0.05 ppm; the 119 Sn chemical shifts (relative to Me 4 Sn) are accurate to +0.1ppm.The 1 3 C spectra are given in Tables 5 and 6a/b.

336


Normawati

Samsodin

et al.

Main Group Metal

Chemistry

Tablel: Analytical data Compound

M.p (° C)

Tetraorqanotms (p- 0(CH2)20CHCeH4)SnPh3 138-140 (p- 0(CH2)20CCH3CeH4)SnPh3 144-146 (p-0:CHCeH4)SnPh3 118-120 (p-0:CCH3CeH4)SnPh3 136-138 (p-HON:CHCeH4)SnPh3 157-159 (p-NH2C(0)NHN:CHC6H4)SnPh3 159-161 (p-HON:CCH3CeH4)SnPh3 171-173 (p-NH2C(0)NHN:CCH3CeH4)SnPh3 174-176 Trioraanotins (p-0(CH2)20CHCeH4)SnPh20H

%C

%H

%N

64.21 (64.97) 65.17 (65.53) 65.57 (65.98) 66.18 (66.56) 63.51 (63.87) 60.83 (60.97) 64.38 (64.50) 61.39 (61.63)

4.53 (4.85) 5.03 (5.11) 4.21 (4.43) 4.41 (4.73) 4.36 (4.50) 4.45 (4.79) 4.67 (4.79) 4.53 (4.79)

2.84 (2.98) 8.12 (8.20) 2.73 (2.89) 7.87 (7.99)

4.41 57.28 (57.45) (4.59) 58.29 4.79 102-104 (58.32) (4.89) 3.97 57.69 (57.77) (4.08) 94-96 58.58 4.37 (4.44) 98-100 (58.73) 54.97 3.37 122-124 (3.66) (55.15) 3.98 56.03 (56.19) (4.01) 126-128 64.98 4.68 (4.71) 137-139 (62.13) 4.87 62.49 (62.67) 142-144 (4.93) 51.93 4.42 (52.02) 163-165 (4.53) 52.65 4.59 (52.79) (4.76) 167-169 X = -0C(0)(CH2)2C(0)CeH5; ° Y = -0C(0)CH2SC(S)NMe 96-98

(p-0(CH2)20CCH3CeH4)SnPh20H (p-0:CHC6H4)SnPh20H (p-0:CCH3CeH4)SnPh20H (p-0:CHCeH4)SnPh2CI (p-0:CCH3CeH4)SnPh2CI (p-OCCH^OCHCeH^SnPhpc" (p-0(CH2)20CCH3C6H4)SnPh2Xb (p-0(CH2)20CHC6H4)SnPh2Yc (p-0(CH2)20CCH3CeH4)SnPh2Yc a

Calculated values in parentheses;

b

2.24 (2.33) 2.19 (2.28)

RESULTS AND DISCUSSION W h i l e t h e r e h a v e b e e n a f e w a c c o u n t s 8 ' 1 0 in the literature o n t h e s y n t h e s i s of p h e n y l t i n s c a r r y i n g a r i n g s u b s t i t u e n t , Z, w h i c h is a n a c i d i c or r e a c t i v e f u n c t i o n a l g r o u p , t h e s e c o m p o u n d s h a v e largely t e n d e d to be the h o m o l e p t i c s p e c i e s , ( Z - C 6 H 4 ) 4 S n , often o b t a i n e d in unfavourable yields. The multi-step synthesis outlined below (reactions 1-5) affords a c o n v e n i e n t a n d m o d e r a t e l y high y i e l d r o u t e to t h e n e w title c o m p o u n d s , in p a r t i c u l a r ( p f o r m y l p h e n y l ) d i p h e n y l t i n h y d r o x i d e a n d its p - a c e t y l p h e n y l a n a l o g u e . THF p - B r M g C 6 H 4 C R 0 C H 2 C H 2 0 + Ph 3 SnCI

Ph 3 SnC 6 H 4 -p-CR0CH 2 CH 2 0 + MgBrCI

(1)

p-CH3C6H4S03H Ph3SnC6H4-p-CR0CH2CH20

Ph3SnC6H4-p-CR:0

(2)

THF


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Vol. 22, No. 5, 1999

Synthesis

and Spectroscopic

Study

Tetra-Phenyltin

of Heteroleptic

Compounds

Mon-Ring

Containing

Substituted

The p-Forml

Tri-and

or

p-Acetyl

Table 2a: IR data 3 o n s e l e c t e d m o n o - r i n g s u b s t i t u t e d tetra- a n d tri- o r g a n o t i n c o m p o u n d s

IR f r e q u e n c i e s ( c m 1 )

Compound b

1660.2(w) 1208.7(w) 10.1(m)

1587.0(m,sp) 1171.9(w) 728.4(m)

1556.3(w) 1074.1(m) 698.5(m,sp)

1428.1(m) 996.4(w)

1685.7(vs,sp) 1073.7(m) 607.3(w)

1587.2(m,sp) 959.3(s)

1450.3(m) 818.7(m)

1362.3(m) 809.6(m)

1179.5(m) 749.0(m)

(p-HON:CHC6H4)SnPh3'

1641.3(m,br)d 1011(w) 698.5(m,sp)

1548.1 (w) 965.5(m)

1427.9(m,sp) 868.5(m),

1303.2(w) 814.0(m),

1073.9(m) 729.8(s)

(p-H 2 NC(0)HNN:CHC 6 H 4 )SnPh 3 9

1640.1(vs,br)e

1538.3(m)d

1425(m,sp)'

(p-HON:CCH3C6H4)SnPh3°

1639.7(m,br) 200 cm" 119 . The infrared results are thus in accord with the Mössbauer data which support a pentacoordinate tin environment for the triorganotin carboxylates.No shift to lower frequencies of v(C=0) was observed for the ring substituent R C : 0 (R=H,Me) in both the tetraorganotin and triorganotin compounds, indicating that it does not participate as a donor group towards tin. This is also true of the benzoyl fragment in the propionate esters. The tin-119 NMR spectra at ambient temperatures were recorded in CDCI 3 and gave single sharp resonances between -130.1 and -131.5 ppm for the tetraorganotins (Table 4). The chemical shifts are comparable to those observed for Ph 4 Sn (-128.8 ppm), (p-CIC 6 H 4 ) 4 Sn (-119.2 ppm) and ( p - M e C 6 H 4 ) 4 S n (-123.0 ppm). In the 1 3 C-NMR spectra of these compounds (Table 5), it is seen that the para-carbons of the substituted phenyl groups (C4) suffer downfield shifts relative to the para-carbons of the unsubstituted phenyl groups (Cp) on account of the electron withdrawing nature of the para-substituents. The downfield shifts follow the order: RC0(CH 2 ) 2 0