Synthesis of novel Copolymers from free radical polymerization of D-Fructopyranose derivatives and N-Substituted Maleimides

Ezat . H . Zmam
Department of Chemistry , College of Science, University of Kerbala, Iraq

(NJC)
(Received on  15/9/2004)		(Accepted for publication on  22/6/2005)

Abstract
Several N - substituted maleimides were prepared from the reaction of maleic anhydride with aromatic primary amines to form the corresponding N- substituted maleamicacids. Dehydration of the prepared  maleamic acids using acetic anhydride and sodium acetate resulted in the formation of the corresponding maleimides. The prepared maleimides were allowed to polymerize with D-fructopyranose derivatives   (compound (II)) free radically using AIBN   As the initiator .
The prepared compounds were detected by using C.H.N Analyses , I.R  and physical properties.  
الخلاصة
حضرت مجموعة من الماليئمايدات المعوضة من خلال تفاعل انهيدريدالماليك مع عدد من الأمينات الأولية الاورمانية للحصول على أحماض الاميك أولاً . بعد ذلك أغلقت الحلقة من خلال سحب جزيئة ماء عن طريق تفاعل أحماض الاميك مع انهايدريد الخلات واسيتات الصوديوم . 
ثم حضرعدد  من البولميرات المشتركة من خلال تفاعل الماليئمايدات المعوضة مع مشتق سكر الفركتوز من خلال تفاعلات البلمرة بالجذور الحرة باستخدام  AIBN    كبادئ . 
شخصت جميع المركبات المحضرة باستخدام جهاز التحليل للعناصر وأطياف الأشعة تحت الحمراء ودراسة الخواص الفيزيائية.
Introduction
Fructopyranosyl  derivatives were prepared recently (1-2) because of their biological activity (3-5), also used in most of carbohydrates synthesis ( 6). Polyamides are well known polymers for their thermal stabilitie (7-10However homopolymerization of N-substituted maleimide have produced low molecular weight  polymers in general (11-13),while copolymerization of N-substituted maleimides have resulted in higher molecular  weight but the products showed lower (Tg) values (14,15).  This paper reports the results of copolymerization of several N- substituted maleimides with compound (II) free radically using AIBN   as the initiator .
Experimental 
All solvents used were redistilled, I.R-spectra were recorded on a Shimadzu I.R- 408– spectrophotometer. Elemenal analyses was preformed using a perkin - Elmer 204 B . Instrument . 
Preparation of  2, 3- 4,5 - Di - O - isopropylidene - -D- Fructopyranose (I)
Zinc chloride ( 24 gm ) was added to a solution of ( 30 gm ) of D-fructose in dry acetone (150ml) , then (1-1.5 ml)of phosphoric acid . The temperature was kept at 30Co with continuous stirring  for 24-48 hrs. The reaction mixture was neutralized with ( 18 gm of k2CO3 in 100 ml H2 O ). The mixture was evaporated under reduced pressure,and The residual syrup was extracted with chloroform ( 3x50 ml) , washed many times with water , and dried over magnesium sulphate .The solution was filtered off . The syrup residue was cooled to obtain white crystals . The product was recrystallized  from  n-hexane to give colorless crystals .
Yield ( 80%) , m.p = 46Co        
Anal.calc.for  C12 H20 O6   : C% (50.38) , H% (7.69)
Found  : C % (51.l ), H % ( 7.43 ) 
I.R data showed the appearance of aband of (-OH ) at 3250 cm-1 ,( C-H ) at 2980cm-1 and aband assigned for (C-O-C) cyclic ether linkage at (1235-1245 Cm-1) . 
preparation of 2,3 4,5- Di-O- Isopropylidene-l-O-acryloate -D- fryctopyranosyl (II)
 ( lgm) of compound ( I ) was dissolved in  ( 5ml)of dry beryzene and (5ml)dry pyridine . then ( 3ml) of acryloylchloride was added dropwise with stirring in an  Ice bath, the stirring was continous for 24hrs .The reaction mixture was diluted with (20ml) of water then ( 10 % ) HCL and extracted with chloroform ( 20x3ml), the organic layer was washed several times with water to remove the salt and unreacted materials , and dried over anhydrous sodium sulphate . The drying agent was  filtered off and the filterate was evaporated under redused pressure to give crude syrup (75% ) yield.
Anal.calc. for C 15 H 22 O7 : C% ( 57.32) H % ( 7.O) 
Found : C% ( 56.77) H% (7.11) 
I.R data shows disappearance of ( -OH) band and appearance of ester
(C = O ) band at 1740 Cm-1  with vinylic  (C = C ) at 1440 Cm-1
Preparation of N- substituted Amic Acids.
N-aryl substituted Maleamic acids were prepared according to litreature(15,16). They were purified by either crystallization or by dissolving the amic acid in the least amount of sodium bicarbonate solution followed by precipitation using HCL . Table-1-lists the m.p, percent yields and C.H.N Analyses.

Table-1- Melting points , percent yields and C.H.N  Analyses.
C%           H%        N %	Yield %	M.P
(Co)	Amic Acid	
62.8         4.71        7.31 61.9         4.66        7.29	Calc .  found	
98	   
198.5	N-phenyl  Maleamic acid 	
53.2         3.54        6.2    
54.o         3.44        6.7 	Calc .  Found	
97	       
     195                                   	N-(4-chloro phenyl) maleamic acid 	
 69.7        4.56        5.8 69.4         4.11        5.99	Calc .  Found	
98	      
140	N-(1-naphthyl) Malemic acid 	
50.84       3.38        11.86 51.2         3.42        10.73	Calc .  Found	
98	      
      203	N-(3-nitro phenyl ) maleamic acid 	
64.39       5.36         6.83 63.97       6.11         6.77	Calc .  Found	
96	     
     192	N-(4-methyl phenyl ) maleamic acid	

Dehydration of the prepared N-aryl maleamic acid
	The prepared N-substituted maleamic acids were cyclized by dehydration using acetic anhydride - sodium acetate acorroding to literature (16,17). Table -2- lists the melting points, percent yields , and C.H.N  Analyses.

Table -2- Melting points , percent yields and C.H.N Analyses .

Maleimide
	
M.P(Co)	
Yield %	
C%       H%     N%	

N-phenyl   Maleimide	
78.3	
86	
Calc . found	
69.36   4.04    8.09 68.91   4.11    7.91	

N-(4-chloro phenyl) Maleimide 	
76	
115	
Calc . found	
57.83    2.89   6.74 56.91    3.01   6.82	

N-(1-naphthyl)  Maleimide	
80	
109	
Calc . found	
75.33    4.03    6.27 74.98     4.1     6.32	

N-(3-nitro phenyl )  Maleimide 	
77	
127	
Calc . found	
59.40    2.97    6.93 58.89    2.97    6.87	

N-(4-methyl phenyl )  Maleimide  	
80	
149	
Calc . found	
70.58    4.81     7.48 70.44     4.72    7.77	

CO - polymerization of several - N -aryl maleimides with compound (II)free radically .
	Equimolar quantities of N-substituted maleimides and comp. (II).were placed in a polymerization bottle . few milligrams of ( AIBN ) were added to the mixture . the mixture dissolved in DMF solvent , and the bottle was purged with dry pure nitrogen gas before stoppering the container quickly. The bottle was placed in a water bath provided with athermometer.
	The polymerization mixture was heated to 70Co in case of using   (AIBN )  as the Initiator and to  85 Co  when benzoyl peroxide was used .
	The mixture after heating for an hour was poured into a beaker  containing methanol. precipitate was formed , then filtered and washed with water and purified by dissolving in benzene and precipitated with carbon tetra chloride .This process was repeated until pure material was obtained . Table ( 3 ) lists names of the prepared copolymers along their softening points , percent conversions , purification solvents and viscosities .

Table-3-Softening points , percent conversions , purification solvents and Viscosities .

[η]a	Purification  solvent	S.P
C°	%
conversion	CO- polymer	

0 . 49	

Benzene – CCl4	

180-200	

80	Poly [ N-phenyl maleimide -CO- 2,3-4,5- Di - O- Isopro pyidine - l-O- acryloate - D-fructopyranosyl ] 	

0. 61	

Hot ethanol water	

180-195	

65	Poly [N-4- chloro phenyl maleimide- CO- 2,3 -4,5- Di- O- Isoproylidine l-O-acryloate - D-fructopyranosyl] 	

0 . 40
	
Benzene  Chloroform	

170-190	

50	Poly [ N-l-naphthyl  maleimide -CO- 2,3-4,5-Di-o-Isopropy lidine-l-O-acryloate- D-fructopyranosyl ] 	

0 . 51	

Benzene  ether	

175-197	

76	Poly [ N-3-nitro phenyl maleimide-CO-2,3-4,5 Di-O-Isopropylidine-l-O-acryloate-D-fructopyranosyl ]   	

0 . 43	

Benzene – CCl4	

160-185	

46	Poly [ N-4-methyl phenyl maleimide -CO-2,3-4,5-Di-O-Isoprpylidine- l-O- acryloate - D-fructopyranosyl ] 	

 ( a ) -   The viscosities were measured in CH2Cl2 

Results and discussion
	Compound ( II ) was allowed to CO-polymerize with several N-aryl substituted maleimides using free radical chain growth polymerization .
N- substituted maleimides were prepared starting with reacting of maleic anhydride and primary aromatic amines to form several N-aryl substituted maleamic acids in high yield. 
	Table (1) lists the physical properties of prepared amic acids elemental analyses showed good agreement of the calculated and the found percentages and also I.R spectrum shows appearance of  ( C = O ) band at (1700 - 1720 cm-1 )and      ( C = C ) aromatic at ( 1400 - 1480 cm-1 ) .The amic acid allowed to react with acetic anhyderide, sodium acetate mixture according to literature (16,17). These compounds were characterized by C.H.N Analyses and I.R spectram which showed     ( C = O ) at 1675 cm-1  and ( C-N) band at 1135 cm-1  with aromatic ( C = C ) at ( 1470 cm-1 ) . yields of the corresponding N-aryl maleimides were fair and were used for copolymerization with compound ( II ) using AIBN or benzyl peroxide as the initiator . Table ( 3 ) lists softening points , viscositiesand solvents used for purification of the prepared copolymers . I.R spectrams were used to detect copolymers wich showed the major absorption bands like ( C = O) at   ( 1700 cm-1 ) , aromatic ( C = C ) at ( 1420 - 1480 cm-1 ) , (C-O-C) cyclic ether at (1250 cm-1) and disappear ance of vinylic ( C = C )band.

مخطط يوضح سير التفاعلات 

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