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

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing 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 102 (Melting point / Melting Range)

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

GLP compliance:

no

Type of method:

differential scanning calorimetry

Key result

Atm. press.:

ca. 1 atm

Decomposition:

yes

Decomp. temp.:

ca. 204 °C

Remarks on result:

other: No melting point could be determined. Substance showed softening at temperature range of 70 to 135 °C followed by decomposition at around 204°C

The first DSC measurement wth a heating rate of 10 K/min showed an endothermal effect in the temperature range of 70 - 130 °C. A second edothermal effect was observed in the temperature range 235 - 270 °C and an exothermal effect starting at approx. 440 °C.

The second measurement with a heating rate of 10 K/min showed an endothermal effect in the temperature range of 70 - 130 °C. This measurement was terminated at 150 °C to ensure that the endothermal effect was a melting/softening effect.

The third measurement with a heating rate of 10 K/min showed an endothermal effect in the temperature range of 70 - 135 °C. A second endothermal effect was observed in the temperature range 230 - 270 °C. This 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: Melting point (DSC measurements)

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 hole	Black residue, mass loss: 78%
2	9.37	25	150	70 - 130	77.4	Aluminium with hole	Test item was a clear melt
3	9.12	25	300	70 - 135 230 - 270	78.0 237.5	Aluminium with hole	Test item was a black melt, mass loss: 22%

Due to the course of the first endothermal effect and the low energy consumption during this endothermal effect, it was concluded that the test item did not actually melt. It was concluded that the test item softened in the temperature range of 70 -135 °C.

Conclusions:

The test item softened in the temperature range of 70 -135 °C under atmospheric conditions but did not actually melt. The test item started to decompose at a temperature of approximately 204°C.

Executive summary:

The melting point / melting range of the test item was determined by DSC measurement according to OECD 102. The study showed that the test item has no exact melting point but softened in the temperature range between 70 - 135 °C. The test item started to decompose at a temperature of approximately 204°C.

Description of key information

The melting point / melting range of the test item was determined by DSC measurement according to OECD 102. The study showed that the test item has no exact melting point but softened in the temperature range between 70 - 135 °C. The test item started to decompose at a temperature of approximately 204 °C.