3,9-Diethylidene-2,4,8,10-tetraoxaspiro(5.5)undecane

3,9-Diethylidene-2,4,8,10-tetraoxaspiro[5.5]undecane (DETOSU) is a bicyclic ketene acetal derived from the isomeric allyl acetal 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]undecane (DVTOSU). As a bifunctional monomer, DETOSU is an important building block for polyorthoesters formed by the addition of diols to the activated double bond of the diketene acetal.[1]

3,9-Diethylidene-2,4,8,10-tetraoxaspiro[5.5]undecane
Names
Preferred IUPAC name
3,9-Diethylidene-2,4,8,10-tetraoxaspiro[5.5]undecane
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.254.405
UNII
Properties
C11H16O4
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Preparation

DETOSU is prepared in a rearrangement reaction of DVTOSU, it is an exothermic reaction that also occurs spontaneously with complete conversion.[2] For production on an industrial scale, the rearranged is carried out at elevated temperatures in the presence of catalysts.

The rearrangement reaction can be carried out in alkaline medium (such as with n-butyllithium in ethylenediamine[3] or potassium tert-butoxide in ethylenediamine[4]) but also photochemically by UV irradiation in the presence of iron pentacarbonyl as catalyst and triethylamine in boiling pentane[5] or with dichlorotris(triphenylphosphine)ruthenium(II) / sodium carbonate in bulk.[6][7]

In order to obtain purities sufficient for the use as a monomer, the crude product (obtained after the rearrangement reaction and vacuum distillation) must be recrystallized several times from pentane. The yields of pure product are about 50%.[3]

Properties

3,9-Diethylidene-2,4,8,10-tetraoxaspiro[5.5]undecane is, when pure, a crystalline material at room temperature.[3] Because of its low crystallization tendency, it is mostly used as a liquid. DETOSU is relatively unstable. It hydrolyzes rapidly even in the presence of only water traces and spontaneously isomerizes during storage to the diallylacetal DVTOSU, which is inactive for the polymerization.[8] The pure substance is very reactive against the attack of electrophilic agents and ows a strong tendency for cationic polymerization.[6] A characteristic property of DETOSU is the intense IR band at 1700 cm−1, which is also used to monitor the conversion in the rearrangement reaction.

Use

The diketene acetal 3,9-diethylidene-2,4,8,10-tetraoxaspiro[5.5]undecane, DETOSU, is a reactive bifunctional monomer that forms biodegradable polyorthoesters by polyaddition with α,ω-diols.

Polyorthoesters are used as embedding media for pharmaceuticals in extended release formulations for controlled drug release by surface erosion under physiological conditions.[9]

gollark: Features.
gollark: I'll admit the code is a bit bad now but PotatOS Hypercycle is coming soon with *major* refactors.
gollark: <@!259973943060856833> Like what?
gollark: WRONG!
gollark: PotatOS is able to make omnidisks somewhat unduplicateable, *but* that only works because their value comes from being cryptographically signed and able to run in privileged mode on potatOS - you can run them anywhere else, it just won't be useful.

References
  1. Heller, J.; Himmelstein, K. J. (1985). "Poly(ortho ester) biodegradable polymer systems". Methods in Enzymology. 112: 422–436. doi:10.1016/S0076-6879(85)12033-1. PMID 3930918.
  2. Pişkin, E. (2002). "Biodegradable Polymers in Medicine". In Scott, Gerald (ed.). Degradable Polymers: Principles and Applications (2nd ed.). Kluwer Academic Press. pp. 321–378. doi:10.1007/978-94-017-1217-0_10. ISBN 1-4020-0790-6.
  3. US 5939453, J. Heller, S.Y. Ng, "PEG-POE, PEG-POE-PEG, and POE-PEG-POE block copolymers"
  4. US 4532335, R.F. Helwing, "Preparation of ketene acetals by rearrangement of allyl and substituted allyl acetals"
  5. US 6863782, P.W. Newsome et al., "Method of preparing di(ketene acetals)"
  6. Crivello, J. V.; Malik, R.; Lai, Y.-L. (1996). "Ketene acetal monomers: Synthesis and characterization". J. Polym. Sci. A Polym. Chem. 34 (15): 3091–3102. doi:10.1002/(SICI)1099-0518(19961115)34:15<3091::AID-POLA1>3.0.CO;2-0.
  7. Heller, Jorge (2011). "Poly(Ortho Esters)". In Lendlein, Andreas; Sisson, Adam (eds.). Handbook of Biodegradable Polymers: Isolation, Synthesis, Characterization and Applications. Wiley-VCH. doi:10.1002/9783527635818.ch4. ISBN 978-3-527-32441-5.
  8. Heller, Jorge (1993). "Poly(Ortho Esters)". In Langer, Robert S.; Peppas, Nicholas A. (eds.). Biopolymers I. Advances in Polymer Science. Berlin / Heidelberg: Springer-Verlag. pp. 41–92. ISBN 3-540-56148-X.
  9. Heller, Jorge (1990). "Development of poly(ortho esters): A historical overview". Biomaterials. 11 (9): 659–665. doi:10.1016/0142-9612(90)90024-K.
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