N-benzoyl-5'-O-(p,p'-dimethoxytrityl)-2'-deoxycytidine

Boiling point

Link to relevant study record(s)

Reference

Endpoint:

boiling point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-11-08 to 2018-04-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 103 (Boiling Point)

Qualifier:

according to guideline

Guideline:

EU Method A.2 (Boiling Temperature)

GLP compliance:

no

Type of method:

differential scanning calorimetry

Remarks:

Capillary method measurement was performed to clarify the results of the DSC measurements

Key result

Atm. press.:

ca. 1 atm

Decomposition:

yes

Decomp. temp.:

ca. 204 °C

Remarks on result:

other: No boiling point could be determined after the softening effect and before the decomposition started

Two DSC measurements in aluminium crucibles with a hole showed an endothermal effect after the softening in the temperature range of 230 - 270 °C. In the first DSC measurement, an exothermic effect was observed starting at approximately 440 °C. In both measurements, the mass loss was incomplete (78% and 22%, respectively). The second measurement was terminated at 300 °C to determine whether the second endothermal effect was a boiling effect. The results of the DSC measurements are summarized in Table 1 below:

Table 1: Boiling point (DSC measurement)

DSC run	Test item / mg	Starting temperature / °C	Final test temperature / °C	Temperature range (endothermal) / °C	Onset / °C	Crucible	Observations after the measurement
1	9.76	25	500	70 - 130 235 - 270	78.5 237.8	Aluminium with a hole	Black residue, mass loss: 78%
2	9.12	25	300	70 - 135 230 - 270	78.0 237.5	Aluminium with a hole	Test item was a black melt, mass loss: 22%

A measurement with the capillary method was performed to clarify the results of the DSC measurements. Since this measurement was performed only as a verifying screening, a high heating rate of 10 K/min was chosen and therefore the absolute temperature values derived with the capillary method are not as accurate as the DSC results. The filling height of the test item was approximately 5 mm. The results of the measurement are summarized in Table 2.

Table 2: Results of the capillary method

No.	Set point / °C	Heating rate / K/min	End point / °C	Remarks
1	200	10	300	Approx. 200 °C: test item was a clear melt Approx. 204 °C: yellow solids formed in the clear melt Approx. 220 °C: test item showed discolouring to orange Approx. 240 °C: test item started boiling, solids were formed at the capillary wall Approx. 254 °C: test item boiled and showed discolouring to black Approx. 265 °C: test item stopped boiling Approx. 271 °C: weak bubble formation Approx. 271 - 310 °C: no further change

The capillary method measurement showed that the test item decomposed before the boiling occurred.

Under consideration of the results from the DSC measurements and the capillary method it was concluded that the test item showed no boiling after the softening effect and before the decomposition started. Decomposition started at approx. 204 °C.

Conclusions:

The test item showed no boiling point at atmospheric pressure before decomposition started. The test item started to decompose at approx. 204 °C.

Executive summary:

The boiling point / boiling range of the test item was investigated by DSC measurement according to OECD 103. Under consideration of the results from the DSC measurements and the capillary method it was concluded that the test item showed no boiling after the softening effect and before the decomposition started. The study showed that the test item starts to decompose at a temperature of approx. 204 °C. The test item has no boiling point under atmospheric conditions.

Description of key information

The boiling point / boiling range of the test item was investigated by DSC measurement according to OECD 103. Under consideration of the results from the DSC measurements and the capillary method it was concluded that the test item showed no boiling after the softening effect and before the decomposition started.The study showed that the test item starts to decompose at a temperature of approx. 204 °C. The test item has no boiling point under atmospheric conditions.