The question is from INChO - Indian National Chemistry Olympiad. I'm typing the question as such first.... I'll show my working also
I just want to know if I'm correct....4.8 Draw the structure of dimethyl 1,2-cyclobutene dicarboxylate (J)
is heated with maleic anhydride(butenedioic anhydride), an unusual reaction takes place to form compound K
. When K
is boiled with aq. NaOH and the solution is acidified, compound L
), which is optically inactive, is obtained. 1.0g of L reacts with 77.5mL of 0.2M NaOH.4.9 Equivalent weight of compound L is _________4.10 The no. of -COOH groups present in compound L is ________4.11 L is expected to contain (Mark X for all the appropriate choices)
(i) Cyclobutane ring ___
(ii) Cyclohexane ring ___
(iii) open chain structure ___
(iv) one double bond ___4.12 Draw the possible structure/s of compound L and compound K.4.13 Draw the structure of a possible intermediate in the reaction.
L on heating forms M
) which on reaction with N
gives a polymer O
.4.14 Draw the structure of a representative segment of polymer O
That's pretty easy
. This is my structure..4.9
As 1.0g of L reacts with (77.5)(0.2) m.eq. of NaOH, equivalent weight is 1000/(15.5) ~64.5 g/eq4.10
no. of -COOH groups in L = (Molecular Wt.)/
(Eq. Weight) = 44.11
Well for this question I've calculated DBE(Double bond equivalent) of L and got '6'. 4 of the 'double bonds' are with 4 -COOH s.
So that leaves L with 2 more unsaturation units .
I expect it may contain a ring (hopefully a cyclohexane ring) and 'may' be a double bond.4.12
Since I've expected L to contain cyclo hexane ring and a double bond, I think the possible reaction in accordance with it is4.13
No idea how the reaction proceeds.. Is it by free-radical mechanism or ... 4.14
I have some vague idea about this but first let's agree upon 'L'.
But there are other approaches also which yield different products..
I'll post them later..